#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    int N; cin >> N;
    ll mi = numeric_limits<ll>::max();
    rep(i,N) {
        string s; cin >> s;
        vector<int> v;
        int d_max = 0;
        for(char c : s) {
            int d = [c]() {
                if(isdigit(c)) return c - '0';
                return c - 'A' + 10;
            }();
            d_max = max(d_max, d);
            v.push_back(d);
        }

        ll B = d_max + 1, POW = 1, val = 0;
        for(int i = int(v.size()) - 1; i >= 0; i--) {
            val += v[i] * POW;
            POW *= B;
        }
        mi = min(mi, val);
    }

    cout << mi << endl;
}