#coding: utf-8
##yuki_314

n=int(raw_input())

dp=[0 for i in xrange(1000001)]

dp[0]=1
dp[1]=2
dp[2]=2
for i in xrange(3,n):
 dp[i]=(dp[i-2]+dp[i-3])%(10**9+7)
 
print dp[n-1]