#include "bits/stdc++.h"
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define rrep(i,n) for( int i = n; i >= 0; i-- )
#define REP(i,s,t) for( int i = s; i <= t; i++ )
#define RREP(i,s,t) for( int i = s; i >= t; i-- )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000
#define int long long

int dp[3][1000010];

signed main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
	int N; cin >> N;
	dp[1][0] = 1;
	rep(i, N) {
		dp[0][i + 1] = dp[2][i] + dp[1][i];
		dp[1][i + 1] = dp[0][i];
		dp[2][i + 1] = dp[1][i];
		rep(j, 3) dp[j][i + 1] %= mod;
	}
	cout << (dp[0][N - 1] + dp[1][N - 1] + dp[2][N - 1]) % mod << endl;

    return 0;
}