fn fib(n: i32) -> i32 {
    if n == 0 || n == 1 {
        return n;
    }

    var grandparent = 0;
    var parent = 1;
    var me = 0;

    for i in 0..n-1 {
        me          = parent + grandparent;
        grandparent = parent;
        parent      = me;
    }

    return me;
}

print(fib(0));
print(fib(1));
print(fib(2));
print(fib(3));
print(fib(4));
print(fib(5));