let fibo = fun n ->
    let rec fibo_inner = fun i -> fun last -> fun last_last ->
        ifzero (n - i) then
            last + last_last
        else
            fibo_inner (i+1) (last + last_last) last
    in

    ifzero n then
        1
    else ifzero (n - 1) then
        1
    else
        fibo_inner 2 1 1
    in

let x = print fibo 0 in
let x = print fibo 1 in
let x = print fibo 2 in
let x = print fibo 3 in
let x = print fibo 4 in
let x = print fibo 5 in
let x = print fibo 6 in
let x = print fibo 7 in
print fibo 8