/* -*- coding: utf-8 -*-
 *
 * 164.cc: No.164 ちっちゃくないよ!! - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 1000;

typedef unsigned long long ull;
const ull LINF = 1ULL << 63;

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  int n;
  cin >> n;

  ull minvv = LINF;
  for (int i = 0; i < n; i++) {
    string sv;
    cin >> sv;

    char maxch = 0;
    for (int j = 0; j < sv.size(); j++)
      if (maxch < sv[j]) maxch = sv[j];

    int b;
    if (maxch < '2') b = 2;
    else if (maxch <= '9') b = maxch - '0' + 1;
    else b = maxch - 'A' + 11;
    //printf("maxch = %c, b = %d\n", maxch, b);

    ull vv = 0;
    for (int j = 0; j < sv.size(); j++) {
      int d = (sv[j] <= '9') ? sv[j] - '0' : sv[j] - 'A' + 10;
      vv = vv * b + d;
    }
    if (minvv > vv) minvv = vv;
  }

  printf("%llu\n", minvv);
  return 0;
}