import std.stdio;
import std.string;
import std.conv;
import std.algorithm;
import std.range;
import std.array;

/// base2num ==============
auto base2num(string numberString, int base){
  string base36 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  long res;
  foreach(i, c; numberString.dup.reverse){
    res += base36.indexOf(c) * base.to!long^^i;
  }
  return res;
}

/// detectBase =======================
int detectBase(string s){

  string base36 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  int base;
  foreach(i; s){
    base = max(base, base36.indexOf(i).to!int + 1);
  }
  return base;
}

/// main =======
void main(){
  auto N = readln.strip.to!int;
  long res = long.max;
  foreach(i; 0..N){
    auto buf = readln.strip;
    auto base = detectBase(buf);
    res = min(res, base2num(buf, base));
  }
  writeln(res);
}