#include "bits/stdc++.h"
#define _CRT_SECURE_NO_WARNINGS
#define rep(i,n) for(int i = 0;i < n;i++)
#define REP(i,n,k) for(int i = n;i < k;i++)
#define P(p) cout << (p) << endl;
#define sP(p) cout << setprecision(15) << fixed << p << endl;
#define vi vector<int>
#define printv(v) for(int i = 0;i < v.size();i++)P(v[i]);
#define printt(a,b) cout << a << " " << b << endl; 
#define mp(a,b) make_pair(a,b)
#define pb(a) push_back(a)

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
int dx[] = { 1, -1 , 0 , 0};
int dy[] = { 0,  0,  1, -1};
int MOD = 1e9 + 7;

ll dp[1000000][4];
void solve() {
  ll n;
  cin >> n;
  dp[1][1] = 1;
  dp[2][2] = 1;
  dp[3][3] = 1;
  REP(i,1,n){
    dp[i+1][1] = (dp[i+1][1]+dp[i][2]+dp[i][3])%MOD;
    dp[i+2][2] = (dp[i][1]+dp[i+2][2]+dp[i][3])%MOD;
    dp[i+3][3] = (dp[i][1]+dp[i][2]+dp[i+3][3])%MOD;
  }
  ll ans = (dp[n][1]+dp[n][2]+dp[n][3])%MOD;
  P(ans);
}

int main() {
  solve();
  return 0;
}