fn ackermann(m int, n int ) int {
    if m == 0 {
        return n + 1
    }
    else if n == 0 {
        return ackermann(m - 1, 1)
    }
    return ackermann(m - 1, ackermann(m, n - 1) )
}

fn main() {
    for m := 0; m <= 4; m++ {
        for n := 0; n < ( 6 - m ); n++ {
            println('Ackermann($m, $n) = ${ackermann(m, n)}')
        }
    }
}