#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <iomanip>
#include <cassert>
using namespace std;

#define GET_ARG(a,b,c,F,...) F
#define REP3(i,s,e) for (i = s; i <= e; i++)
#define REP2(i,n) REP3 (i,0,(int)(n)-1)
#define REP(...) GET_ARG (__VA_ARGS__,REP3,REP2) (__VA_ARGS__)
#define RREP3(i,s,e) for (i = s; i >= e; i--)
#define RREP2(i,n) RREP3 (i,(int)(n)-1,0)
#define RREP(...) GET_ARG (__VA_ARGS__,RREP3,RREP2) (__VA_ARGS__)
#define DEBUG(x) cerr << #x ": " << x << endl

const int LOOPS = 1e4;

double dp[2][101];

int main(void) {
    int i, j, p, q;
    cin >> p >> q;
    dp[0][p] = 1.0 / 3.0;
    double ans = 1.0 / 3.0;
    REP (i,LOOPS) {
        REP (j,0,100) dp[1-i%2][j] = 0;
        REP (j,0,100) {
            ans += dp[i%2][j] * j / 100 / 2 + dp[i%2][j] * (100 - j) / 100 / 3;
            dp[1-i%2][min(100,j+q)] += dp[i%2][j] * (100 - j) / 100 / 3;
            dp[1-i%2][max(0,j-q)] += dp[i%2][j] * j / 100 / 2;
        }
    }
    printf("%.8f\n",ans);
    return 0;
}