import std.algorithm, std.container, std.conv, std.math, std.range, std.typecons, std.stdio, std.string;

auto rdsp(){return readln.splitter;}
void pick(R,T)(ref R r,ref T t){t=r.front.to!T;r.popFront;}
void readV(T...)(ref T t){auto r=rdsp;foreach(ref v;t)pick(r,v);}

void main()
{
  int n; readV(n);

  auto r = long.max;
  foreach (_; 0..n) {
    string s; readV(s);
    auto c = s.maxElement.toD+1;

    auto d = 0L;
    foreach (i, si; s)
      d += si.toD * c^^(s.length-i-1);

    r = min(r, d);
  }

  writeln(r);
}

auto toD(dchar c) { return cast(long)(c < 'A' ? c-'0' : c-'A'+10); }