I. Pom Gana

#include <bits/stdc++.h>
using namespace std;

int main(){
    int tc;
    scanf("%d", &tc);
    for(int tr = 1; tr <= tc; tr++){
        int n, m;
        scanf("%d %d", &n, &m);

        int graph[n][n];
        for(int r = 0; r < n; r++){
            for(int c = 0; c < n; c++){
                graph[r][c] = 0;
            }
        }

        for(int i = 0; i < m; i++){
            int r, c;
            scanf("%d %d", &r, &c);
            graph[r-1][c-1]++;
        }

        int pom = 0;
        for(int p = 0; p < n; p++){
            int out = 0;
            int in = 0;

            for(int c = 0; c < n; c++){
                if(graph[p][c] > 0) out++;
            }

            for(int r = 0; r < n; r++){
                if(graph[r][p] > 0) in++;
            }
            //cout << "p = " << p << " in: " << in << " Out: " << out << endl;
            if((in > 0 && out == 0) || (out > 0 && in == 0)) pom++;
        }

        printf("Case %d: %d\n",tr, pom);

    }
    return 0;
}