#include<iostream>
#include<fstream>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<set>
#include<string>
#include<cmath>
using namespace std;

#define REP(i,m,n) for(int i=(m); i<(int)(n); i++)
#define RREP(i,m,n) for(int i=(int)(n-1); i>=m; i--)
#define rep(i,n) REP(i,0,n)
#define rrep(i,n) RREP(i,0,n)
#define fi first
#define se second

#ifdef _DEBUG
ifstream ifs("input");
#define input ifs
#else
#define input cin
#endif
#define DEBUG(x) cout<<#x<<": "<<x<<endl

using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;

const double PI = (1*acos(0.0)); 
const double INF = 1e9;
const double EPS = 1e-9;
const double mod = 1e9 + 7;


int main(){
    int x,p;
    input >> x >> p;
    printf("%.7lf", ceil(x/2.0) * (100.0/p));
    return 0;
}
