#include <iostream>
#include <stdlib.h>

#define N 1000000
#define M 1000000007

using namespace std;

int main(void)
{
  static long step1[N]={0};
  static long step2[N] = {0};
  static long step3[N] = {0};
  int n;
  cin >> n;
  step1[0] = 1; step2[0] = 0; step3[0] = 0;
  step1[1] = 0; step2[1] = 1; step3[1] = 0;
  step1[2] = 1; step2[2] = 1; step3[2] = 1;

  for(int i = 3; i < n; i++) {
    step1[i] = (step2[i-1] + step3[i-1])%M;
    step2[i] = (step1[i-2] + step3[i-2])%M;
    step3[i] = (step1[i-3] + step2[i-3])%M;
  }
  cout << ((step1[n-1] + step2[n-1] + step3[n-1])%M) << endl;
  return 0;
}