-- A
local a,b,c,d,e,k = io.read("n", "n", "n", "n", "n", "n")
local tbl = {a,b,c,d,e}

for i=1, #tbl - 1 do
    for j=i+1, #tbl do
        local distance = tbl[j] - tbl[i]
        if distance > k then
            print(":(")
            return
        end
    end
end

print("Yay!")