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

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

dp = [-1] * (10**6+5)
for i in range(1,N+1):
    if i==1:
        dp[i] = 1
    elif i==2 or i==3:
        dp[i] = 2
    else:
        dp[i] = (dp[i-2] + dp[i-3]) % m
print(dp[N])