POJ-1323 Game Prediction

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <vector>
#include <climits>
#include <set>

using namespace std;

int num[55];
int main()
{
    //freopen("in.txt", "r", stdin);
    int n, m, cas = 0;

    while(cin >> m >> n)
    {
        if(n == 0 && m == 0)
            break;
        int t= n * m, sum = 0;
        set<int> s;
        for(int i = 0; i < n; i++)
            cin >> num[i];
        sort(num, num+n);

        for(int i = n-1; i >= 0; i--)
        {
            if(num[i] == t)
                sum++;
            else
                s.insert(num[i]);
            t--;
            while(s.count(t))
                t--;
        }
        printf("Case %d: %d\n", ++cas, sum);
    }
    return 0;
}