#include<iostream>
#include<cstring>
#include<vector>
#include<algorithm>
#include<cstdio>
#define MAX_N 103
#define INF 50000000
using namespace std;

int T;
int N;

int d[MAX_N][MAX_N];

struct edge {
public:
    int u, v, c;

    edge(int uu, int vv, int cc) : u(uu), v(vv), c(cc) { }

    edge() { }
};

edge E[MAX_N*MAX_N];
int tot=0;

int main() {
    scanf("%d", &T);
    int cas = 0;
    while (T--) {
        tot = 0;
        scanf("%d", &N);
        for (int i = 0; i < N; i++)
            for (int j = 0; j < N; j++) {
                scanf("%d", &d[i][j]);
                if (i != j)E[tot++] = edge(i, j, d[i][j]);
            }
        int cnt = tot;
        bool flag = true;
        for (int i = 0; i < tot; i++) {
            int u = E[i].u, v = E[i].v, c = E[i].c;
            int tmp = INF;
            for (int j = 0; j < N; j++) 
                if (j != u && j != v)
                    tmp = min(tmp, d[u][j] + d[j][v]);
            if (tmp > d[u][v])continue;
            if (tmp < d[u][v]) {
                flag = false;
                break;
            }
            cnt--;
        }
        printf("Case %d: ", ++cas);
        if (flag)
            printf("%d\n", cnt);
        else
            printf("impossible\n");
    }
    return 0;
}