class Solution:
    def firstUniqChar(self, s):
        seen = dict()
        for x in range(len(s)):
            if s[x] in seen:
                seen[s[x]][0] += 1
            else:
                seen[s[x]] = [1, x]
        
        result = None
        for key, val in seen.items():
            if val[0] == 1 and (result is None or val[1] < result):
                result = val[1]
                
        if result is None:
            return -1
        
        return result
                
s = Solution()
print("Expected: 0")
print("Got:", s.firstUniqChar("leetcode"))