#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
ll mod = 1e9 + 7;

ll dp[1000001][3];

int main() {
  int n;
  cin >> n;
  dp[0][0] = 1;
  for(int i = 0; i < n; i++) {
    dp[i+1][0] = (dp[i][1] + dp[i][2]) % mod;
    dp[i+1][1] = dp[i][0];
    dp[i+1][2] = dp[i][1];
  }

  cout << ((dp[n][0] + dp[n][1]) % mod + dp[n][2]) % mod << endl;
}