/* -*- coding: utf-8 -*-
 *
 * 787.cc:  No.787 Mice and Traitors(ネズミ達と裏切り者) - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

// u=p*q+(1-p)*(1-q)

int main() {
  double p, q;
  scanf("%lf%lf", &p, &q);

  p /= 100, q /= 100;
  double u = p * q + (1.0 - p) * (1.0 - q);
  printf("%.13lf\n", p * q / u * 100);
  return 0;
}