array = []
array << gets.chomp.to_i
array << gets.chomp.to_i
array << gets.chomp.to_i
array << gets.chomp.to_i
array << gets.chomp.to_i
k = gets.chomp.to_i

combinations = array.combination(2).to_a
combinations.each do |c|
    if c[0] > c[1] then
        dist = c[0] - c[1]
    else
        dist = c[1] - c[0]
    end
    if dist > k then
        puts ":("
        exit()
    end
end
puts "Yay!"