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

void main(string[] args)
{
    long n;
    readf("%d\n", &n);
    auto s = readln.strip.split(" ");
    writeln(roundRobin(s[0], s[1]).array);
}
