use correct base ptr
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 95ecfe2..27492c8 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -1975,8 +1975,9 @@
         return 127;
 
     kind = PyUnicode_KIND(unicode);
-    startptr = PyUnicode_DATA(unicode) + start * kind;
+    startptr = PyUnicode_DATA(unicode);
     endptr = startptr + end * kind;
+    startptr += start * kind;
     switch(kind) {
     case PyUnicode_1BYTE_KIND:
         return ucs1lib_find_max_char(startptr, endptr);