#include <algorithm>
#include <iostream>
#include <memory.h>
#include <iterator>
#include <cassert>
#include <fstream>
#include <iomanip>
#include <cstdlib>
#include <bitset>
#include <vector>
#include <cstdio>
#include <string>
#include <queue>
#include <deque>
#include <cmath>
#include <ctime>
#include <stack>
#include <set>
#include <map>

using namespace std;

const int N = (int)5000 + 10;
const int INF = (int)1e9 + 10;

int n, k, m;
vector < vector<int> > g;
vector<int> mt;
vector<char> used;

bool try_kuhn (int v) {
    if (used[v])  return false;
    used[v] = true;
    for (size_t i = 0; i < g[v].size(); ++i) {
        int to = g[v][i];
        if (mt[to] == -1 || try_kuhn (mt[to])) {
            mt[to] = v;
            return true;
        }
    }
    return false;
}

int main ()
{
    freopen("input.txt" , "r" , stdin);
    //freopen("output.txt" , "w" , stdout);
    ios_base::sync_with_stdio(false);

    cin >> n >> k;
    for(int i = 0; i < k; ++i) {
        for(int j = 0; j < n; ++j) {
            int x; cin >> x;
            if(x == 1) {
                g[i].push_back(j);
            }
        }
    }

    mt.assign (k, -1);
    for (int v = 0; v < n; ++v) {
        used.assign (n, false);
        try_kuhn (v);
    }

    for (int i = 0; i < k; ++i)
        if (mt[i] != -1)
            printf ("%d %d\n", mt[i]+1, i+1);

    return 0;
}