#include <bits/stdc++.h>

using namespace std;
using ll = long long;

int main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);

    long double a, b, c, d;
    cin >> a >> b;
    c = a*b;
    d = c+(100.l-a)*(100.l-b);
    cout << fixed << setprecision(18) << c/d*100.l << '\n';

    return 0;
}