#include <iostream>

using namespace std;

static const long long MOD = 1000000007LL;

int main() {
	int n;
	cin >> n;
	long long result;
	if (n == 1) {
		result = 1;
	} else {
		long long kk = 1;
		long long kp = 1;
		long long pk = 0;
		for (int i = 2; i < n; ++i) {
			long long nextKk = pk;
			long long nextKp = (kk + pk) % MOD;
			long long nextPk = kp;
			kk = nextKk;
			kp = nextKp;
			pk = nextPk;
		}
		result = (kk + kp + pk) % MOD;
	}
	cout << result << endl;
	return 0;
}