diff --git a/lib/main.go b/lib/main.go
index da18257..b24d078 100644
--- a/lib/main.go
+++ b/lib/main.go
@@ -63,7 +63,7 @@ var (
 		`^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}$`)
 
 	regexpRFC3339 *regexp.Regexp = regexp.MustCompile(
-		`^([0-9]+)-(0[1-9]|1[012])-(0[1-9]|[12][0-9]|3[01])[Tt]([01][0-9]|2[0-3]):([0-5][0-9]):([0-5][0-9]|60)(\.[0-9]+)?(([Zz])|([\+|\-]([01][0-9]|2[0-3]):[0-5][0-9]))$`)
+		`^(\d+)-(0[1-9]|1[012])-(0[1-9]|[12]\d|3[01])[Tt]([01]\d|2[0-3]):([0-5]\d):([0-5]\d|60)(\.\d+)?(([Zz])|([\+|\-]([01]\d|2[0-3]):[0-5]\d))$`)
 
 	regexpCommaAlphaNum *regexp.Regexp = regexp.MustCompile(
 		`[^A-Za-z0-9,]`)