题解 | #找出字符串中第一个只出现一次的字符#

import sys

def findstr(x):
    process_result = []
    delete_result = []
    result = []
    for i in x:
        if i not in process_result:
            process_result.append(i)
        else:
            process_result.remove(i)
            delete_result.append(i)
    for i in process_result:
        if i not in delete_result:
            result.append(i)
    if len(result) != 0:
        return result[0]
    else:
        return -1
    
while True:
    try:
        str1 = input()
        if len(str1) > 0:
            print(findstr(str1))
        else:
            break          
    except:
        break