#include <bits/stdc++.h>

using namespace std;

using ll = long long;

double calc(int n, int p) {
    return 100.0 * n / p;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int x, p;
    cin >> x >> p;
    double ans = 0;
    if (x % 2 == 0) {
        ans = calc(x / 2, p);
    } else {
        ans = calc((x-1)/2, p) * p / 100 + calc((x+1)/2,p) * (100-p)/100 + 1;
    }
    cout << fixed << setprecision(15) << ans << endl;
    return 0;
}