#include <bits/stdc++.h>
using namespace std;

signed main(){
  int N; cin >> N;
  vector< string > A( N );
  for( int i = 0; i < N; ++i )
    cin >> A[ i ];
  long long ans = ~( 1LL << 63 );
  for( int i = 0; i < N; ++i ){
    int base = 0;
    for( int j = 0; j < A[ i ].size(); ++j )
        base = max( base, A[ i ][ j ] <= '9' ? A[ i ][ j ] - '0' + 1 : A[ i ][ j ] - 'A' + 10 + 1 );
    for( int j = 0; j < A[ i ].size(); ++j )
        if( A[ i ][ j ] >= 'A' )
            A[ i ][ j ] = A[ i ][ j ] - 'A' + 'a';
    ans = min( ans, stoll( A[ i ], nullptr, base ) );
  }
  cout << ans << endl;
  return 0;
}