#!/usr/bin/python
# -*- coding: utf-8 -*-

#定义一个斐波那契数列

def Fibonacci(n):
    fn1 = 1
    fn2 = 1
    fn3 = 1
    while n>2:
        fn3 = fn1 + fn2
        fn1 = fn2
        fn2 = fn3
        n -= 1
    return fn3

s = int(input())
n = 0
while True:
    n += 1
    if Fibonacci(n) > s :
        print(Fibonacci(n))
        break