/* -*- coding: utf-8 -*-
 *
 * 533.cc: No.533 Mysterious Stairs - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 1000000;
const int K = 3;

typedef long long ll;
const ll MOD = 1000000007;

/* typedef */

/* global variables */

ll dp[MAX_N + 1][K + 1];

/* subroutines */

/* main */

int main() {
  int n;
  cin >> n;

  dp[0][0] = 1;
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= K; j++)
      if (i >= j)
	for (int k = 0; k <= K; k++)
	  if (j != k) dp[i][j] += dp[i - j][k], dp[i][j] %= MOD;

  ll sum = 0;
  for (int j = 1; j <= K; j++) sum += dp[n][j];
  printf("%lld\n", sum % MOD);
  
  return 0;
}