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

struct cww{cww(){
    ios::sync_with_stdio(false);cin.tie(0);
    cout<<fixed;
    cout<<setprecision(10);
}}star;
#define fin "\n"
#define FOR(i,bg,ed) for(int i=(bg);i<(ed);i++)
#define REP(i,n) FOR(i,0,n)
#define fi first
#define se second
#define pb push_back
#define DEBUG if(0)
template <typename T>inline void chmin(T &l,T r){l=min(l,r);}
template <typename T>inline void chmax(T &l,T r){l=max(l,r);}
template <typename T>
istream& operator>>(istream &is,vector<T> &v){
    for(auto &it:v)is>>it;
    return is;
}
double p;
double f(LL x){
    x/=2;
    return x/p;
}
int main(){
    LL x;
    cin>>x>>p;
    p/=100;
    if(x%2)cout<<1+p*f(x-1)+(1-p)*f(x+1)<<endl;
    else cout<<f(x)<<endl;
    return 0;
}
