Row with minimum 1's

#include<iostream>
#include<cstdio>
#include<climits>
using namespace std;

int main(){
    int t; scanf("%d", &t);
    while(t--){
        int n, m; scanf("%d %d", &n, &m);
        int a[n][m], i,j;
        int ans = INT_MAX, index = -1;
        for(i = 0; i < n; i++){
            int num = 0;
            for(j = 0; j < m; j++){
                int k; scanf("%d", &k);
                if(k == 1) num++;
            }
            if(num < ans && num != 0){
                ans = num;
                index = i;
            }
        }
        if(ans == 0) cout << "-1\n";
        else cout << index << endl;
    }
}