1 #include <iostream>
2 #include <algorithm>
3 #include <string>
4
5 #define MOD 1000000007
6 using namespace std;
7
8 long long quick_pow(long long a, long long b, long long c){
9 long long ans = 1;
10 a = a%c;
11 while (b > 0){
12 if (b % 2 == 1){
13 ans = (ans*a) % c;
14 }
15 b = b / 2;
16 a = (a*a) % c;
17 }
18 return ans;
19 }
20
21 int main(){
22 ios::sync_with_stdio(false);
23 /*
24 freopen("in.txt", "r", stdin);
25 freopen("out.txt", "w", stdout);
26 */
27 long long x;
28 while (cin >> x){
29 x++;
30 long long ans = quick_pow(3, x, MOD);
31 ans--;
32 ans = ans * 500000004 % MOD;
33 cout << ans << endl;
34 }
35 //fclose(stdin);
36 //fclose(stdout);
37 //system("pause");
38 return 0;
39 }
