#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < n; i++)
using ll = long long;
using graph = vector<vector<int>>;

const ll mod = 1000000007;
const int INF = 1001001001;

ll modpow(ll a, ll p){
    ll ret = 1;
    while(p){
        if(p&1) ret = ret * a % mod;
        a = a * a % mod;
        p >>= 1;
    }
    return ret;
}

ll dp[1000007];

int main() {
    dp[0] = 1;
    ll n; cin >> n;
    //i秒後にAにいる場合の数
    for(int i = 0; i <= n; i++){
        dp[i+1] = (mod + modpow(3, i) - dp[i]) % mod;
    }
    cout << dp[n] << endl;
}