diff --git a/src/hb-icu.cc b/src/hb-icu.cc
index 8ee49c2..287f863 100644
--- a/src/hb-icu.cc
+++ b/src/hb-icu.cc
@@ -65,8 +65,8 @@
   if (unlikely (script == HB_SCRIPT_INVALID))
     return USCRIPT_INVALID_CODE;
 
-  unsigned int maxScriptCode = u_getIntPropertyMaxValue(UCHAR_SCRIPT);
-  for (unsigned int i = 0; i <= maxScriptCode; i++)
+  unsigned int numScriptCode = 1 + u_getIntPropertyMaxValue (UCHAR_SCRIPT);
+  for (unsigned int i = 0; i < numScriptCode; i++)
     if (unlikely (hb_icu_script_to_script ((UScriptCode) i) == script))
       return (UScriptCode) i;