# 斐波那契数列。
# 利用递归的思想
import time

t1 = time.time()


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


print(fib(45))
t2 = time.time()
print(t2 - t1)