求6和9组成的最大字符串

# coding=utf-8
import sys


def solution(num):
    # 代码可以写这里
    num = str(num)
    newNum = []
    flag = 0
    for item in num:
        if flag == 0 and item == '6':
            item = '9'
            flag = 1
        newNum.append(item)
    num = ''.join(newNum)
    return num


def main():
    # 读取第一行的n
    # firstline = sys.stdin.readline().strip()
    firstline = 696
    print(solution(firstline))


if __name__ == "__main__":
    main()