#include "iostream"
#include "iomanip"
using namespace std;

long double X;
long double rad;
long double ans;

int main() {
	cin >> X >> rad;
	if ((long long int)X % 2 == 0) {
		for (int i = 0; i < 10000000; i++) {
			ans = (ans + X - rad / 100 * ans + (100.0 - rad) / 100 * ans) / 2;
		}
	}
	else {
		for (int i = 0; i < 10000000; i++) {
			ans = (ans+1 + X - rad / 100 * ans + (100.0 - rad) / 100 * ans) / 2;
		}
	}
	cout << setprecision(15) << ans<<"\n";
	return 0;
}