#include <bits/stdc++.h>

using namespace std;


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

    int n;
    cin >> n;

    vector<map<int, int>> reels(n);

    for(int i = 0; i < n; ++i){
        long long reel_in;
        cin >> reel_in;

        for(int j = 9; j >= 0; --j){
            int l = reel_in % 10;
            reel_in /= 10;

            reels[i][l] = j;
        }
    }

    set<int> button_presses;
    int min_time = 100000;

    for(int i = 0; i < 10; ++i){
        button_presses.clear();

        for(int j = 0; j < n; ++j){
            int time = reels[i][j];
            while(button_presses.count(time)){
                time += 10;
            }
            button_presses.insert(time);

            if(time < min_time){
                min_time = time;
            }
        }
    }

    cout << min_time << endl;

    cout << flush;

    return 0;
}