#include <algorithm>
#include <iostream>
#include <iomanip>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <cmath>
using namespace std;

#define FOR(i,s,e) for (int i = int(s); i < int(e); i++)
#define FORIT(i,c) for (typeof((c).begin()) i = (c).begin(); i != (c).end(); i++)
#define ISEQ(c) (c).begin(), (c).end()

int main(){
	int N;
	cin >> N;

	long ret;
	if (N == 1){
		ret = 1;
	}else{
		long pk = 0;
		long kk = 1;
		long kp = 1;
		long pk_old;
		long kk_old;
		long kp_old;
		while(N > 2){
			kp_old = kp;
			kk_old = kk;
			pk_old = pk;

			pk = kp_old;
			kk = pk_old;
			kp = (pk_old + kk_old) % 1000000007;

			N--;
		};
		ret = (pk + kk + kp) % 1000000007;
	}

	cout << ret << endl;
	return 0;
}