#include<iostream>
using namespace std;

int INF=1e9+7;

int main() {
	int n;
	cin >> n;
	int dp[1100000][4];
	for(int i=0;i<1100000;i++){
	    for(int j=0;j<4;j++)dp[i][j]=0;
	}
	dp[1][1]=1;
	dp[2][2]=1;
	dp[3][3]=1;
	for (int i = 1;i <= n;i++) {
		dp[i + 1][1] += (dp[i][2] + dp[i][3])%INF;
		dp[i + 2][2] += (dp[i][1] + dp[i][3])%INF;
		dp[i + 3][3] += (dp[i][1] + dp[i][2])%INF;
	}
	cout << (dp[n][1] + dp[n][2] + dp[n][3])%INF << endl;
}