diff --git a/src/main/scala/io/github/acl4s/FenwickTree.scala b/src/main/scala/io/github/acl4s/FenwickTree.scala
index b9171ef..a5f10ef 100644
--- a/src/main/scala/io/github/acl4s/FenwickTree.scala
+++ b/src/main/scala/io/github/acl4s/FenwickTree.scala
@@ -2,7 +2,7 @@ package io.github.acl4s
 
 import scala.reflect.ClassTag
 
-import io.github.acl4s.internal.rightOpenInterval
+import io.github.acl4s.internal.{rightOpenInterval, IPair}
 
 /**
  * Reference: https://en.wikipedia.org/wiki/Fenwick_tree
@@ -34,7 +34,7 @@ case class FenwickTree[T: ClassTag](n: Int)(using m: AddSub[T]) {
   }
 
   def sum(range: Range): T = {
-    val (l, r) = rightOpenInterval(range)
+    val IPair(l, r) = rightOpenInterval(range)
     sum(l, r)
   }
 
diff --git a/src/main/scala/io/github/acl4s/LazySegtree.scala b/src/main/scala/io/github/acl4s/LazySegtree.scala
index 559e834..09650e5 100644
--- a/src/main/scala/io/github/acl4s/LazySegtree.scala
+++ b/src/main/scala/io/github/acl4s/LazySegtree.scala
@@ -2,7 +2,7 @@ package io.github.acl4s
 
 import scala.reflect.ClassTag
 
-import io.github.acl4s.internal.{ceilPow2, rightOpenInterval}
+import io.github.acl4s.internal.{ceilPow2, rightOpenInterval, IPair}
 
 final case class LazySegtree[S, F](
   n: Int
@@ -48,7 +48,7 @@ final case class LazySegtree[S, F](
   }
 
   def prod(range: Range): S = {
-    val (l, r) = rightOpenInterval(range)
+    val IPair(l, r) = rightOpenInterval(range)
     prod(l, r)
   }
 
@@ -89,7 +89,7 @@ final case class LazySegtree[S, F](
   }
 
   def applyRange(range: Range, f: F): Unit = {
-    val (l, r) = rightOpenInterval(range)
+    val IPair(l, r) = rightOpenInterval(range)
     applyRange(l, r, f)
   }
 
diff --git a/src/main/scala/io/github/acl4s/ModInt.scala b/src/main/scala/io/github/acl4s/ModInt.scala
index 6756af1..2a1f557 100644
--- a/src/main/scala/io/github/acl4s/ModInt.scala
+++ b/src/main/scala/io/github/acl4s/ModInt.scala
@@ -4,13 +4,15 @@ import scala.annotation.targetName
 
 import io.github.acl4s.internal.{Barrett, LPair}
 
-private[acl4s] inline def applyIntImpl(value: Int, mod: Int): Long = {
-  applyLongImpl(value.toLong, mod)
+private[acl4s] inline def applyIntImpl(value: Int, mod: Int): Int = {
+  var x = value % mod
+  if (x < 0) { x += mod }
+  x
 }
 
 private[acl4s] inline def applyLongImpl(value: Long, mod: Int): Long = {
-  var x = value % mod.toLong
-  if (x < 0L) { x += mod.toLong }
+  var x = value % mod
+  if (x < 0L) { x += mod }
   x
 }
 
@@ -174,7 +176,7 @@ object StaticModInt {
 
   def apply[T <: Int](value: Int)(using m: Modulus[T]): StaticModInt[T] = {
     val x = applyIntImpl(value, m.value)
-    new StaticModInt(x.toInt)
+    new StaticModInt(x)
   }
 
   def apply[T <: Int](value: Long)(using m: Modulus[T]): StaticModInt[T] = {
@@ -285,7 +287,7 @@ object DynamicModInt {
 
   def apply(value: Int): DynamicModInt = {
     val x = applyIntImpl(value, bt.m)
-    new DynamicModInt(x.toInt)
+    new DynamicModInt(x)
   }
 
   def apply(value: Long): DynamicModInt = {
diff --git a/src/main/scala/io/github/acl4s/Segtree.scala b/src/main/scala/io/github/acl4s/Segtree.scala
index 61956a4..1f34e96 100644
--- a/src/main/scala/io/github/acl4s/Segtree.scala
+++ b/src/main/scala/io/github/acl4s/Segtree.scala
@@ -2,7 +2,7 @@ package io.github.acl4s
 
 import scala.reflect.ClassTag
 
-import io.github.acl4s.internal.{ceilPow2, rightOpenInterval}
+import io.github.acl4s.internal.{ceilPow2, rightOpenInterval, IPair}
 
 final case class Segtree[T](
   n: Int
@@ -30,7 +30,7 @@ final case class Segtree[T](
   }
 
   def prod(range: Range): T = {
-    val (l, r) = rightOpenInterval(range)
+    val IPair(l, r) = rightOpenInterval(range)
     prod(l, r)
   }
 
diff --git a/src/main/scala/io/github/acl4s/internal/Range.scala b/src/main/scala/io/github/acl4s/internal/Range.scala
index d46b076..0163faf 100644
--- a/src/main/scala/io/github/acl4s/internal/Range.scala
+++ b/src/main/scala/io/github/acl4s/internal/Range.scala
@@ -1,12 +1,12 @@
 package io.github.acl4s.internal
 
-private[acl4s] def rightOpenInterval(range: Range): (Int, Int) = {
+private[acl4s] def rightOpenInterval(range: Range): IPair = {
   assert(range.step == 1 || range.step == -1)
   if (range.isEmpty) {
-    (range.start, range.start)
+    IPair(range.start, range.start)
   } else if (range.step > 0) {
-    (range.start, range.last + 1)
+    IPair(range.start, range.last + 1)
   } else {
-    (range.last, range.start + 1)
+    IPair(range.last, range.start + 1)
   }
 }
diff --git a/src/main/scala/io/github/acl4s/internal/Tuple.scala b/src/main/scala/io/github/acl4s/internal/Tuple.scala
index 47556fe..a0bafbc 100644
--- a/src/main/scala/io/github/acl4s/internal/Tuple.scala
+++ b/src/main/scala/io/github/acl4s/internal/Tuple.scala
@@ -1,3 +1,4 @@
 package io.github.acl4s.internal
 
+final case class IPair(a: Int, b: Int)
 final case class LPair(a: Long, b: Long)
diff --git a/src/test/scala/io/github/acl4s/internal/RangeSuite.scala b/src/test/scala/io/github/acl4s/internal/RangeSuite.scala
index b00c2fb..dd87fff 100644
--- a/src/test/scala/io/github/acl4s/internal/RangeSuite.scala
+++ b/src/test/scala/io/github/acl4s/internal/RangeSuite.scala
@@ -3,17 +3,17 @@ package io.github.acl4s.internal
 class RangeSuite extends munit.FunSuite {
 
   test("rightOpenInterval()") {
-    assertEquals(rightOpenInterval(0 to 10), (0, 11))
-    assertEquals(rightOpenInterval((0 to 10).reverse), (0, 11))
-    assertEquals(rightOpenInterval(10 to 0 by -1), (0, 11))
+    assertEquals(rightOpenInterval(0 to 10), IPair(0, 11))
+    assertEquals(rightOpenInterval((0 to 10).reverse), IPair(0, 11))
+    assertEquals(rightOpenInterval(10 to 0 by -1), IPair(0, 11))
 
-    assertEquals(rightOpenInterval(0 until 10), (0, 10))
-    assertEquals(rightOpenInterval((0 until 10).reverse), (0, 10))
-    assertEquals(rightOpenInterval(10 until 0 by -1), (1, 11))
+    assertEquals(rightOpenInterval(0 until 10), IPair(0, 10))
+    assertEquals(rightOpenInterval((0 until 10).reverse), IPair(0, 10))
+    assertEquals(rightOpenInterval(10 until 0 by -1), IPair(1, 11))
 
-    assertEquals(rightOpenInterval(0 to 0), (0, 1))
-    assertEquals(rightOpenInterval((0 until 0).reverse), (0, 0))
-    assertEquals(rightOpenInterval(0 until 0 by -1), (0, 0))
+    assertEquals(rightOpenInterval(0 to 0), IPair(0, 1))
+    assertEquals(rightOpenInterval((0 until 0).reverse), IPair(0, 0))
+    assertEquals(rightOpenInterval(0 until 0 by -1), IPair(0, 0))
   }
 
 }