import std.stdio, std.conv, std.string, std.math, std.regex, std.range, std.ascii, std.algorithm;

void main(){
	auto a = readln.chomp.to!int;
	auto b = readln.chomp.to!int;
	auto c = readln.chomp.to!int;
	auto d = readln.chomp.to!int;
	auto e = readln.chomp.to!int;
	auto k = readln.chomp.to!int;

	if((b-a) <= k && (c-a) <= k && (d-a) <= k && (e-a) <= k && (c-b) <= k && (d-b) <= k && (e-b) <= k && (d-c) <= k && (e-c) <= k && (e-d) <= k){
		writeln("Yay!");
	} else {
		writeln(":(");
	}
}