#include <bits/stdc++.h>
#include "bits/stdc++.h"
#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <string>
#include <sstream>
#include <cmath>
#include <stack>
#include <queue>
#include <cctype>
#include <stdio.h>
#include <map>
#include <unordered_map>
#include <string.h>
#include <utility>

typedef long long ll;

#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
using namespace std;

typedef pair<int, int> P;

ll dp[1000001][4];

int main() {

	int n=0;
	cin>>n;

	dp[1][1] =1;
	dp[2][2]=1;
	dp[3][1] =1;
	dp[3][2] =1;
	dp[3][3] =1;

	for(int i=4; i<=n; i++){

		dp[i][1] = (dp[i-1][2]+dp[i-1][3])%1000000007;

		dp[i][2] = (dp[i-2][1]+dp[i-2][3])%1000000007;

		dp[i][3] = (dp[i-3][1]+dp[i-3][2])%1000000007;
	}

	cout<<(dp[n][1]+dp[n][2]+dp[n][3])%1000000007<<endl;


}