#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using pii = pair<int, int>;

int main() {
    int x;
    double p;
    cin >> x >> p;
    p /= 100;
    double res = 0;
    if(x & 1) {
        res = 1 + (x - 1.0) / 2 + (1 - p) * (x + 1.0) / 2 / p;
    } else {
        res = x / 2.0 / p;
    }
    cout << fixed << setprecision(10) << res << endl;
}
