#include<iostream>
#include<string>

using namespace std;

#define NMAX 1000000
#define MOD 1000000007
int main(){

	int N;
	int dp[NMAX+1]={0};

	dp[0]=1;

	cin>>N;

	for(int i=0;i<=N;i++){
		for(int j=2;j<=3&&i+j<=N;j++){
			dp[i+j]+=dp[i];
			dp[i+j]%=MOD;
		}
	}

	int ans=0;
	if(N>=1) ans+=dp[N-1],ans%=MOD;
	if(N>=2) ans+=dp[N-2],ans%=MOD;
	ans+=dp[N],ans%=MOD;

	cout<<ans<<endl;
}