#include <iostream>
#include <stdio.h>

using namespace std;

int x;
double p;

int main(void)
{
	cin >> x >> p;
	p /= 100;
	
	double ans;
	if(x % 2 == 0){
		ans = x/2/p;
	}
	else{
		ans = p*(x-1)/2/p + (1-p)*(x+1)/2/p + 1;
	}
	printf("%.11f\n", ans);
	return 0;
}