#include<iostream>

#include<cstdio>

#include<cstring>

#include<algorithm>

using namespace std;

char code[1000][100];

bool solve(int p)

{

    for(int i = 1; i < p; i++)

    {

        int len = min(strlen(code[i-1]), strlen(code[i]));

        int j;

        for(j = 0; j < len; j++)

        {

            if(code[i-1][j] != code[i][j])

                break;

        }

        if(j == len)

            return false;

    }

    return true;

}

int cmp(void const *va, void const *vb)

{

    char *a = (char*)va;

    char *b = (char*)vb;

    return strcmp(a, b);

}

int main()

{

    int d = 0;

    while(scanf("%s", code[0]) != EOF)

    {

        int p = 1;

        while(scanf("%s", code[p]) && code[p][0] != '9') { p++;}

        qsort(code, p, sizeof(code[0]), cmp);       /*这里sizeof内的要注意*/

        if(solve(p))

            printf("Set %d is immediately decodable\n", ++d);

        else

            printf("Set %d is not immediately decodable\n", ++d);

    }

}

qsort介绍：https://www.runoob.com/cprogramming/c-function-qsort.html

思考：为什么要先排序再查找，不排序为何样例不通过？