#include <bits/stdc++.h>
using namespace std;
using lint = long long;
const lint MOD = 1e9+7;

signed main(){
  int n; cin >> n;
  vector<vector<lint> > dp(n + 1, vector<lint> (3, 0));
  dp[0][0] = 1;
  for(int i = 0; i < n; i++){
    dp[i + 1][1] += dp[i][0];
    dp[i + 1][2] += dp[i][1];
    dp[i + 1][0] += dp[i][1] + dp[i][2];
    for(int j = 0; j <= 2; j++) dp[i + 1][j] %= MOD;
  }
  lint ans = 0;
  for(int i = 0; i <= 2; i++) ans += dp[n][i], ans %= MOD;
  cout << ans << endl;
}