unittest
{
	assert( [ "1", "2", "4", "8", "9", "15" ].parse.expand.solve == "Yay!" );
	assert( [ "15", "18", "26", "35", "36", "18" ].parse.expand.solve == ":(" );
}



import std.conv;
import std.range;
import std.stdio;
import std.typecons;

void main()
{
	stdin.byLineCopy.parse.expand.solve.writeln;
}

auto parse( Range )( Range input )
if( isInputRange!Range && is( ElementType!Range == string ) )
{
	auto a = input.front.to!( long );
	input.popFront;
	auto b = input.front.to!( long );
	input.popFront;
	auto c = input.front.to!( long );
	input.popFront;
	auto d = input.front.to!( long );
	input.popFront;
	auto e = input.front.to!( long );
	input.popFront;
	auto k = input.front.to!( long );
	return tuple( a, b, c, d, e, k );
}

auto solve( long a, long b, long c, long d, long e, long k )
{
	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 )
	{
		return "Yay!";
	}
	else
	{
		return ":(";
	}
}
