# -*- coding: utf-8 -*-

N = int(input())
modulo = 10**9 + 7

dp = [-1] * (10**6+1)
def solution(n):
    if dp[n] > -1:
        return dp[n]

    num = -1
    if n==1:
        num = 1
    elif n==2 or n==3:
        num = 2
    else:
        num = solution(n-2) + solution(n-3)
    
    dp[n] = num
    return dp[n]

print(solution(N) % modulo)