diff --git a/buggy.py b/buggy.py
--- a/buggy.py
+++ b/buggy.py
@@ -8,13 +8,13 @@
 
 
 class Solution:
-    def findTheArrayConcVal(self, nums) -> int:
+    def findTheArrayConcVal(self, nums: List[int]) -> int:
         i = 0
         c = 0
         j = len(nums) - 1
         while i <= j:
             if i == j:
-                c = c + num[i]
+                c = c + nums[i]
                 break
             s = str(nums[i]) + str(nums[j])
             c = c + int(s)
