#include <bits/stdc++.h>
using namespace std;
const int mod = 1000000007;
long long f = 0, g = 1;
int n;
int main() {
  cin >> n;
  for (int i = 2; i <= n; i++) {
    long long k = f;
    f = 3 * g % mod;
    g = (k + 2 * g) % mod;
  }
  printf("%lld", f);
  return 0;
}
