#include <iostream>
#include <algorithm>
using namespace std;
int main() {
	int H, A, D;
	//cin >> H >> A >> D;
	H = 49; A = 7; D = 17;

	int CA = min((H + A - 1) / A, ((H + D - 1) / D * 3 + 1)/ 2);
	double C = CA;
	for (int ca = 0; ca <= CA; ca++) {
		int h = H - ca * A;
		double cd = (h + D - 1) / D * 1.5;
		if (ca + cd < C) {
			C = ca + cd;
		}
	}
	cout << C;
}