#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  scanf("%d", &n);
  int a = 1, b = 2, c;
  for (int i = 0; i < n; i++) {
    c = (a + b) % 1000000007;
    a = b;
    b = c;
  }
  printf("%d\n", c - 2);
  return 0;
}
