#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <cmath>
#include <iomanip>
#include <map>
#include <limits>
using namespace std;
typedef long long LL;

int val(char c){
    if('0' <= c && c <= '9') return c - '0';
    return 10 + c - 'A';
}

int main(){
    int N;
    cin >> N;
    LL min_v = numeric_limits<LL>::max();
    for(int i = 0; i < N; i++){
        string s;
        cin >> s;
        int r = 2;
        for(int j = 0; j < s.size(); j++){
            r = max(r, val(s[j])+1);
        }
        LL v = 0;
        for(int j = 0; j < s.size(); j++){
            v *= r;
            v += val(s[j]);
        }
        min_v = min(min_v, v);
    }
    cout << min_v << endl;
    return 0;
}