#include <iostream>
using namespace std;
const int mod = 1e9 + 7;
int N;
int ken = 1, kenken, pa;
int main(void) {
	cin >> N;
	for (int i = 0; i < N - 1; ++i) {
		int _ken = ken, _kenken = kenken, _pa = pa;
		ken = _pa;
		kenken = _ken;
		pa = (1LL * _ken + _kenken) % mod;
	}
	cout << (1LL * ken + kenken + pa) % mod << endl;
	return 0;
}