题解 | 找出字符串中第一个只出现一次的字符

import sys

while True:
    try:
        s = input()
        j = 0
        for i in range(len(s)):
            if s.count(s[i]) == 1:
                print(s[i])
                j = 1
                break
        if j == 0:
            print(-1)
        break
    except:
        break