#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <cmath>
#include <iostream>
#include <queue>
#include <list>
#include <stack>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;

ll calc(string v){
  char mx = '0';
  rep(i,v.size()){
    if('0' <= v[i] && v[i] <= '9'){
      if('0' <= mx && mx <= '9' && v[i] > mx) mx = v[i];
    }else{
      if('0' <= mx && mx <= '9') mx = v[i];
      else if(v[i] > mx) mx = v[i];
    }
  }
  ll p = 0;
  if('0' <= mx && mx <= '9') p = mx-'0';
  else p = (mx-'A') + 10;
  p++;

  ll ret = 0;
  ll pp = 1;
  for(int i=v.size()-1; i>=0; i--){
    ll a = 0;
    if('0' <= v[i] && v[i] <= '9') a = v[i]-'0';
    else a = (v[i]-'A') + 10;
    ret += pp * a;
    pp *= p;
  }
  return ret;
}


int main(){
  int N;
  cin >> N;
  ll ret = -1;
  rep(i,N){
    string v;
    cin >> v;
    ll res = calc(v);
    if(ret < 0) ret = res;
    else ret = min(ret, res);
  }
  cout << ret << endl;
  return 0;
}