#include <iostream>

long long dp[1000001][3] = {0};

using namespace std;

int main(){
  int N;

  cin >> N;

  dp[0][0] = 1;

  for(int i = 1;i < N;i++){
    dp[i][0] = dp[i-1][2];
    dp[i][1] = dp[i-1][0];
    dp[i][2] = dp[i-1][0] + dp[i-1][1];
  }

  cout << (dp[N-1][0] + dp[N-1][1] + dp[N-1][2]) % (long long)(1e9 + 7) << endl;

  return 0;
}