#include <bits/stdc++.h>
using namespace std;
int fx[] = {1, -1, 0, 0};
int fy[] = {0, 0, 1, -1};
int main() {
  long long n;
  cin >> n;
  if (n == 1)
    cout << 1;
  else if (n == 2)
    cout << 3;
  else {
    n += 3;
    long long a = 0, b = 1;
    for (int i = 2; i <= n; i++) {
      long long c = (a + b) % 1000000007;
      a = b % 1000000007;
      b = c % 1000000007;
    }
    cout << (b - 2 + 1000000007) % 1000000007 << '\n';
  }
}
