#include <bits/stdc++.h>
using namespace std;

#define pb         push_back

typedef long long ll;
const ll INF = 1000000000000000000ll;
const ll MOD = 1000000007ll;
const double EPS = 1e-8;

int dp[1000001][3];

int main(void) {
	//ios_base::sync_with_stdio(false);
	//cin.tie(0);
	
	ll n;
	cin >> n;

	dp[0][0] = 1;
	for(int i=1; i<=n; i++){
		dp[i][0] = dp[i-1][1] + dp[i-1][2];
		dp[i][1] = dp[i-1][0];
		dp[i][2] = dp[i-1][1];
		for(int j=0; j<3; j++){
			dp[i][j] %= MOD;
		}
	}

	/*
	for(int i=0; i<=n; i++){
		for(int j=0; j<3; j++){
			printf("%d ", dp[i][j]);
		}
		puts("");
	}
	*/

	ll ans = dp[n][0];
	ans += dp[n][1];
	ans %= MOD;
	ans += dp[n][2];
	ans %= MOD;

	cout << ans << endl;


	
	return 0;
}