#include <bits/stdc++.h>
using namespace std;
int main() {
    int N, K;
    cin >> N >> K;
    vector<string> S(N);
    for (int i = 0; i < N; i++) {
        cin >> S[i];
    }
    
    vector<vector<int>> dist(N, vector<int>(N, 0));
    for (int i = 0; i < N; i++) {
        for (int j = i + 1; j < N; j++) {
            int d = 0;
            for (int k = 0; k < K; k++) {
                d += (S[i][k] ^ S[j][k]) & 1;
            }
            dist[i][j] = d;
            dist[j][i] = d;
        }
    }
    
    vector<double> avgdist(N, 0.0);
    double divisor = N - 1;
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            if (i != j) {
                avgdist[i] += dist[i][j];
            }
        }
        avgdist[i] /= divisor;
    }
    
    int min_index = min_element(avgdist.begin(), avgdist.end()) - avgdist.begin();
    cout << min_index << endl;
    return 0;
}