#include <bits/stdc++.h>
using namespace std;
const int md = 1000000007;
int solve(int n) {
  if (n == 1) return 1;
  if (n == 2) return 3;
  int ans[1 + n], dp[1 + n];
  dp[1] = 1;
  ans[1] = 1;
  dp[2] = 2;
  ans[2] = 3;
  for (int i = 3; i <= n; i++) {
    dp[i] = (dp[i - 1] + dp[i - 2]) % md;
    ans[i] = (ans[i - 1] + dp[i]) % md;
  }
  return ans[n];
}
signed main() {
  int n;
  scanf("%d", &n);
  printf("%d", solve(n));
  return 0;
}
