#include <bits/stdc++.h>
using namespace std;

int main() {
	long long x;
	char a, b;
	long long q;
	cin >> x;
	cin >> a >> b;
	q = (long long)a + (long long)b;
	if (q == 131 || (q == 132 && (long long)a == (long long)b)) {
		printf("%lld", x * 8 / 10);
	} else if ((q == 132 && (long long)a != (long long)b) || q == 134) {
		printf("%lld", x * 7 / 10);
	} else if (q == 133) {
		printf("%lld", x * 6 / 10);
	}
	return 0;
}