#include <iostream>


using namespace std;

#define MOD (1000000000+7)

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

	long long int bS, bK1, bK2;
	long long int aS, aK1, aK2;
	bS = 1;
	bK1 = 0;
	bK2 = 0;

	for( int i = 1; i <= N; i++ ) {
		aS  = bK1%MOD + bK2%MOD;
		aK1 = bS ;
		aK2 = bK1;
		aS  = aS%MOD;
		aK1 = aK1%MOD;
		aK2 = aK2%MOD;
		bS = aS;
		bK1 = aK1;
		bK2 = aK2;
		// cout << "hoge" << endl;
	}

	cout << (aS%MOD+bK1%MOD+bK2%MOD)%MOD << endl;

	return 0;
}