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

void main() {
    const xs = 5.iota.map!(_ => readln.chomp.to!int).array;
    const k = readln.chomp.to!int;
    foreach (i; 0..5) {
        foreach (j; i+1..5) {
            if (xs[j] - xs[i] > k) {
                writeln(":(");
                return;
            }
        }
    }
    writeln("Yay!");
}

