//   up              nup
//u  p*q           p*(1-q)
//nu (1-p)*(1-q)   (1-p)*q

#include <iostream>
using namespace std;
int main(){
    double p,q; cin >> p >> q;
    p /= 100.0; q /= 100.0;
    printf("%.16lf\n", 100* p*q /(p*q + (1-p)*(1-q)));
    return 0;
}