#include <bits/stdc++.h>
using namespace std;
#define all(c) (c).begin(),(c).end()
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define REP(i,m,n) for(int i=(int)(m);i<(int)(n);i++)
#define rep(i,n) REP(i,0,n)
#define iter(c) __typeof((c).begin())
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
#define mem(a) memset(a,0,sizeof(a))
#define pd(a) printf("%.10f\n",a)
#define pb(a) push_back(a)
#define in(a) insert(a)
#define pi M_PI
#define R cin>>
#define F first
#define S second
#define C class
#define ll long long
#define ln cout<<'\n'
template<C T>void pr(T a){cout<<a;ln;}
template<C T,C T2>void pr(T a,T2 b){cout<<a<<' '<<b;ln;}
template<C T,C T2,C T3>void pr(T a,T2 b,T3 c){cout<<a<<' '<<b<<' '<<c;ln;}
template<C T>void PR(T a,int n){rep(i,n){if(i)cout<<' ';cout<<a[i];}ln;}
bool check(int n,int m,int x,int y){return x>=0&&x<n&&y>=0&&y<m;}
const ll MAX=1000000007,MAXL=1LL<<60,dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
typedef pair<int,int> P;

void Main() {
  int p,q;
  cin >> p >> q;
  double dp[2][2][101];
  mem(dp);
  dp[0][0][p]=1;
  double ans=0;
  rep(t,100) {
    rep(i,2) {
      rep(j,101) {
        double x=(double)j/100;
        if(t) {
          ans+=dp[0][i][j]*x/2;
          dp[1][1][max(0,j-q)]+=dp[0][i][j]*x/2;
          ans+=dp[0][i][j]*(1-x)/3;
          dp[1][0][min(100,j+q)]+=dp[0][i][j]*(1-x)/3;
        } else {
          ans+=dp[0][i][j]/3;
          dp[1][0][p]+=dp[0][i][j]/3;
        }
      }
    }           
    rep(i,2)rep(j,101)dp[0][i][j]=dp[1][i][j];
    mem(dp[1]);
  }
  pd(ans);
}

int main() {
  ios::sync_with_stdio(0);cin.tie(0);
  Main();return 0;
}