#include<iostream>
using namespace std;
long double p; int n;
int main() {
	cin >> n >> p; if (n % 2 == 1)n++; p = 100.0l - p; p /= 100.0l;
	long double ans = 1.0l*n / (2 - p * 2);
	printf("%.14Lf\n", ans);
	return 0;
}