#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <queue>
#include <list>
#include <cmath>
#include <stack>
#include <iomanip>

using namespace std;
typedef long long ll;
using Pll = pair<ll,ll>;

const ll INF = 1LL<<60;
const ll MOD = 1000000007;

//cout << fixed << setprecision(10);

int main() {
    ll N;
    cin >> N;

    vector<vector<ll>> dp(N+10,vector<ll>(3));
    dp[0][0]=1;
    for(int i=1;i<=N;i++){
        dp[i][0]=(dp[i-1][1]+dp[i-1][2])%MOD;
        dp[i][1]=(dp[i-1][0])%MOD;
        dp[i][2]=(dp[i-1][1])%MOD;
    }

    ll ans=0;
    for(int i=0;i<3;i++){
        ans=(ans+dp[N][i])%MOD;
    }

    cout << ans << endl;

    return 0;
}