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


void main()
{
    int N = readln.strip.to!int;
    ulong min = ulong.max;
    foreach (i; 0..N) {
        string s = readln.strip;
        ulong ret = minNum(s);
        if (ret < min) min = ret;
    }
    writeln(min);
}

string base36 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

ulong minNum(string n)
{
    char max = n.minPos!"cast(int)a > cast(int)b".front.to!char;
    int base;
    if ('0' <= max && max <= '9') {
        base = (max - '0').to!int + 1;
    } else {
        base = 10 - 'A' + max + 1;
    }
    ulong ret = 0;
    foreach (i, c; n.dup.reverse) {
        ret += base36.indexOf(c) * base ^^ i;
    }
    return ret;
}