function a(k,x1,x2,x3,x4,x5)
local function b()
k = k - 1
return a(k,b,x1,x2,x3,x4)
end
if k <= 0 then return x4() + x5() else return b() end
function K(n)
return function()
return n
print(a(10, K(1), K(-1), K(-1), K(1), K(0)))