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

int N, K;
string G[50];
vector<pair<int, int>> cut_point;

void solve() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    for (int i = 0; i < N; i++) {
        if (G[i][24] != '0') {
            cut_point.push_back({i, 24});
        }
    }
    for (int j = 0; j < N; j++) {
        if (G[24][j] != '0') {
            cut_point.push_back({24, j});
        }
    }
    ranges::sort(cut_point);
    auto [ret_begin, ret_end] = ranges::unique(cut_point);
    cut_point.erase(ret_begin, ret_end);
}

int main() {
    cin >> N >> K;
    for (int i = 0; i < N; i++) {
        cin >> G[i];
    }
    solve();
    cout << ssize(cut_point) << endl;
    for (auto [i, j] : cut_point) {
        cout << i << " " << j << '\n';
    }
}