#include <cstdio>
#include <cmath>

#include <iostream>
#include <vector>
#include <list>
#include <algorithm>

int sub1(char in) {
  if( '0' <= in && in <= '9' ) {
    return (in - '0');
  }
  if( 'A' <= in && in <= 'Z' ) {
    return (in - 'A' + 10);
  }
  return 0;
}

int main() {

  /* default begin */
  long i, j, k;
  long n, m;
  long temp;
  long t;
  std::vector<long> v;
  bool b;
  /* default end */

  std::string str;
  long N;


  std::cin >> N;
  for(i = 0; i < N; i++) {
    
    std::cin >> str;

    long max = 0;
    for(j = 0; j < str.length(); j++) {
      if( max < sub1(str[j]) ) {
	max = sub1(str[j]);
      }
    }
    
    temp = 0;
    for(j = 0; j < str.length(); j++) {
      temp *= (max+1);
      temp += sub1(str[j]);
    }

    v.push_back(temp);

  }

  std::sort(v.begin(), v.end());

  std::cout << v[0] << std::endl;

  return 0;
}