#include<bits/stdc++.h>

using namespace std;

const int mod = 1e9 + 7;
int dp[1000001][4];

int rec(int idx, int pv)
{
  if(idx < 0) return (0);
  if(idx == 0) return (1);
  if(~dp[idx][pv]) return (dp[idx][pv]);
  int ret = 0;
  if(pv != 1) (ret += rec(idx - 1, 1)) %= mod;
  if(pv != 2) (ret += rec(idx - 2, 2)) %= mod;
  if(pv != 3) (ret += rec(idx - 3, 3)) %= mod;
  return (dp[idx][pv] = ret);
}

int main()
{
  int N;
  cin >> N;
  memset(dp, -1, sizeof(dp));
  cout << rec(N, 0) << endl;
}