#include <bits/stdc++.h>

const long mod = 1000000007;

int main() {

  long N;
  long k2[2], k1[2], p1[2];
  std::cin >> N;

  k2[0] = p1[0] = 0;
  k1[0] = 1;
  for(int i = 1; i < N; ++i) {
    k2[1] = k1[0] % mod;
    k1[1] = p1[0] % mod;
    p1[1] = (k2[0] + k1[0]) % mod;
    k2[0] = k2[1];
    k1[0] = k1[1];
    p1[0] = p1[1];
  }

  std::cout << (k2[0] + k1[0] + p1[0]) % mod << std::endl;     
  
  return 0;
}