def fib_loop(num):
    """
    Finds the N-th fibonacci number using ordinary for-loop.

    :param int num: The N-th fibonacci number (index).
    :return: Computed number.
    """
    if num < 2:
        return num

    first, second = 0, 1
    for i in range(2, num + 1):
        first, second = second, first + second
    return second