diff --git a/imgwelcome/imgwelcome.py b/imgwelcome/imgwelcome.py
index 23fbc2e..83e1545 100644
--- a/imgwelcome/imgwelcome.py
+++ b/imgwelcome/imgwelcome.py
@@ -169,9 +169,7 @@ class ImgWelcome:
 
     def _get_suffix(self, num):
         num = str(num)
-        last = num[-1)]
-        if num[-2] == "1":
-          return "th"
+        last = num[len(num)-1:len(num)]
         if last == "1":
             return "st"
         elif last == "2":