#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N =1e6+5;
string v[15];
bool vis[15];
int cou[15];
int m, n;
int cnt = 0;
bool solve() {
	memset(cou, 0, sizeof(cou));
	int x;
	for(int i = 0; i < n; i++){
		for(int j = 0; j < v[i].size(); j++){
			x = v[i][j] - '0';
			if(!x) break;
			if(!vis[x]) {
				cou[x]++;
				break;
			}
		}
	}
	int mn = 100;
	cou[mn] = 0x3f3f3f3f;
	vector <int> del;
	for(int i = 1; i <= m; i++){
		if(vis[i]) continue;
		if(cou[i] < cou[mn]) {
			mn = i;
			del.clear();
			del.push_back(i);
		}
		else if(cou[i] == cou[mn]) {
			del.push_back(i);
		}
	}
	if(m - cnt - del.size() == 1) {
		for(int i = 1; i <= m; i++){
			if(!vis[i] && i != mn) {
				cout << i;
				break;
			}
		}
		return false;
	} else if(m - cnt - del.size() > 0) {
		cnt += del.size();
		for(auto x : del) {
			vis[x] = 1;
		}
		return true;
	} else if (m - cnt - del.size() == 0 ) {
		cout << -cou[mn];
		return false;
	} 

}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);

	
	cin >> m >> n;
	for(int i = 0; i < n; i++){
		cin >> v[i];
	}
	
	while(solve()){
		
	}


	return 0;
}