#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const double PI = acos(-1);

vector<int> encode(const string &s) {
  vector<int> vs;
  for (char c: s) {
    if (isdigit(c)) vs.push_back(c - '0');
    else vs.push_back(c - 'A' + 10);
  }
  return vs;
}

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

  int n;
  cin >> n;
  long long ret = 7LL<<60;
  REP (i, n) {
    string s;
    cin >> s;
    vector<int> vs = encode(s);
    int d  = 1 + *max_element(ALL(vs));
    long long z = 0;
    for (int v: vs)
      z = d * z + v;
    ret = min(ret, z);
  }

  cout << ret << endl;
  
  return 0;
}