def fib(n):
    if n <= 1:
        return n
    return fib(n-1) + fib(n-2)

def fib(n):
    if n <= 1:
        return 1
    return fib(n-1) + fib(n-2)

def fib(n):
    a, b = 0, 1
    for i in range(n-1):
        a, b = b, a + b
    return a

def fib(n):
    fib_list = [0, 1]
    for i in range(2, n):
        fib_list.append(fib_list[i-1] + fib_list[i-2])
    return fib_list[n]