Tetrrahedon 166/E

///https://trello.com/c/r2Wlhzup/52-problem-166e-codeforces
///http://codeforces.com/problemset/problem/166/E
#include <iostream>
using namespace std;
int main()
{
    unsigned long long A=0, D=1;
    unsigned long long A0, D0;

    int n;
    cin>>n;

    for (int i=1; i<=n; i++)
    {
        A0 = 2*A + D;
        D0 = 3*A;

        A = A0%1000000007;
        D = D0%1000000007;
    }
    cout<<D<<endl;

    return 0;
}