#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll=long long;
using ld=long double;
ld pie=3.141592653589793;
ll inf=4444444444444444444;
ll mod=1000000007;
int main(){
    ll n;
    cin >> n;
    vector<vector<ll>>dp(n,vector<ll>(3,0));
    dp[0][1]=1;
    for (ll i = 1; i < n; i++)
    {
        dp[i][1]+=dp[i-1][0];
        dp[i][2]+=dp[i-1][1];
        dp[i][0]+=dp[i-1][1];
        dp[i][0]+=dp[i-1][2];
        dp[i][0]%=mod;
    }
    ll ans=0;
    for (ll i = 0; i < 3; i++)
    {
        ans+=dp[n-1][i];
        ans%=mod;
    }
    cout << ans << endl;
}