#include <iostream>
#include <algorithm>
#include <vector>
#include <deque>
#include <string>
#include <tuple>
#include <functional>
#include <numeric>
#include <cmath>
#include <iomanip>
#include <map>
#include <random>
//#include "toollib.h"
#define INT_MAX 2147483647
#define Loop(i, n) for(int i = 0; i < (int)n; i++)
#pragma warning (disable:4018)

using namespace std;
typedef long long int lint;

//***** Main Program *****
int main() {
	const lint MOD = 1e9 + 7;
	int N;
	cin >> N;
	if (N == 1) cout << 1 << endl;
	else if (N == 2) cout << 2 << endl;
	else {
		vector<lint> a(N - 1), b(N - 1), c(N - 1);
		a[0] = 0;
		b[0] = 1;
		c[0] = 1;
		Loop(i, N - 2) {
			a[i + 1] = c[i];
			b[i + 1] = a[i];
			c[i + 1] = (a[i] + b[i]) % MOD;
		}
		cout << (a[N - 2] + b[N - 2] + c[N - 2])%MOD << endl;
	}
	return 0;
}