UVA 146 ID Codes

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int main()
{
    char s[1000];
    while (~scanf("%s", s))
    {
        if (strcmp(s, "#") == 0) break;
        int y = strlen(s), i;
        for (i = 0; i < y - 1; i++) if (s[i] < s[i + 1]) break;
        if (i == y - 1) printf("No Successor\n");
        else
        {
            next_permutation(s, s + y);
            printf("%s\n", s);
        }
    }
    return 0;
}