#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#include<vector>
#include<string>
#include<map>
#include <climits>

using namespace std;
int num[1005][15];
int bin[15];
int m, n;
int cnt = 0;
bool st[15];
void op()
{
	while (1)
	{
		memset(bin, 0, sizeof(bin));
		for (int i = 0; i < n; i++)
		{
			for (int t = 0; t < m; t++)
			{
				if (num[i][t] == 0) break;
				if (st[num[i][t]]) continue;
				bin[num[i][t]]++;
				break;
			}
		}
			int max = INT_MIN;
			int min = INT_MAX;
			for (int i = 0; i < 10; i++)
			{
				if (bin[i] > max&&!st[i]) max = bin[i];
				if (bin[i] < min&&!st[i]) min = bin[i];
			}
			if (max > min)
			{
				for (int i = 0; i <10 ; i++)
				{
					if (bin[i] == min&&st[i]==false)
					{
						st[i] = true;
					}
				}
			}
			
			else {
				int k = 0;
				for (int i = 0; i < 10; i++)
				{
					if (bin[i] == min && !st[i])
					{
						cnt++;
						k = i;
					}
				}
				if (cnt == 1)
				{
					cout << k;
					return;
				}
				else {
					cout << -bin[k];
					return;
				}
			}
		}
	}



int main(void)
{
	cin >> m >> n;
	for (int i = 0; i < n; i++)
	{
		string aa;
		cin >> aa;
		for (int t = 0; t < aa.size(); t++) num[i][t] = aa[t]-'0';
	}
	op();




	return 0;
}