diff --git a/commenter/commenter.go b/commenter/commenter.go
index f733a20..8918a45 100644
--- a/commenter/commenter.go
+++ b/commenter/commenter.go
@@ -232,9 +232,10 @@ func parseHunkPositions(patch, filename string) (hi []*hunkInfo, err error) {
 			if err != nil {
 				hunkStart = -1
 			}
-			hunkEnd, err := strconv.Atoi(patchGroup[endPos])
-			if err != nil {
-				hunkEnd = -1
+			hunkEnd := -1
+			hunkLength, err := strconv.Atoi(patchGroup[endPos])
+			if err == nil {
+				hunkEnd = hunkStart + hunkLength - 1
 			}
 			hunkInfos = append(hunkInfos, &hunkInfo{
 				hunkStart: hunkStart,