/* -*- coding: utf-8 -*-
 *
 * 314.cc: No.314 ケンケンパ - 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;

typedef long long ll;
const ll MOD = 1000000007;

/* typedef */

/* global variables */

ll dp[MAX_N + 1];

/* subroutines */

/* main */

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

  dp[0] = 1;

  for (int i = 1; i <= n; i++)
    for (int j = 2; j <= 3; j++)
      if (i >= j) dp[i] = (dp[i] + dp[i - j]) % MOD;

  ll sum = 0;
  for (int i = 0; i <= 2; i++)
    if (n >= i) sum = (sum + dp[n - i]) % MOD;
  printf("%lld\n", sum);
  return 0;
}