#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <iomanip>
#include <stdio.h>
#include <algorithm>
#include <math.h>
#include <numeric>
#include <iterator>
#include <fstream>
#include <math.h>

#include <random>
#include <vector>
#include <string>
#include <stack>
#include <set>
#include <map>
#include <deque>
#include <queue>
#include <list>
#include <bitset>
#include <unordered_set>
#include <unordered_map>

#include <random>
#include <ctime>

#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

#define FOR(i, from, to) for (int i = from; i < to; i++)
#define ROF(i, from, to) for (int i = from; i > to; i--)

const long double PI = 3.141592653589793238463;
const int INF = 0x3f3f3f3f;
const int INFS = 1000000000;
const ll M = 1000000007;
const ll LLINF = 1000000000000000000;
const double EPS = 1e-8;

#define int long long

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);

    int x, p;
    cin >> x >> p;
    ld ans;
    int tmp = (x + 1) / 2;
    ans = (ld(100) / ld(p)) * ld(tmp);
    cout << fixed << setprecision(20) << ans << "\n";

    return 0;
}
