#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  long long *output = new long long[n + 1];
  output[0] = 0;
  output[1] = 1;
  for (int i = 2; i <= n; i++) {
    output[i] = (output[i - 1] + output[i - 2]) % 1000000007 + 1;
  }
  cout << (output[n] + output[n - 1]) % 1000000007;
}
