#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <map>
#include <iomanip>
using namespace std;
typedef pair<double, int> PP;

int P, Q;

double bfs() {
	queue<PP> que;
	que.push(make_pair(1./3,P));

	double ans = 1. / 3;
	int cnt = 0;
	while (cnt!=1000000) {
		pair<double,int> p = que.front(); que.pop();
		ans += p.first / 2 * p.second/100;
		ans += p.first / 3 * (100-p.second)/100;

		if(p.second+Q<100) que.push(make_pair(p.first / 3 * (100 - p.second) / 100,p.second + Q));
		else if(p.second!=100) que.push(make_pair(p.first / 3 * (100 - p.second) / 100, 100));
		if(p.second-Q>0)que.push(make_pair(p.first / 2 * p.second / 100,p.second - Q));
		else if(p.second!=0) que.push(make_pair(p.first / 2 * p.second / 100, 0));
		cnt++;
	}
	return ans;
}

int main()
{
	cin >> P >> Q;
	cout <<fixed<<setprecision(7)<< bfs() << endl;

    return 0;
}