#include <algorithm>
#include <bitset>
#include <cassert>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <unordered_set>
#include <unordered_map>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

int p, q;
double dp[101][101];

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> p >> q;

  double ret = 0.0;
  dp[0][0] = 1.0;
  REP (i, 100) {
    REP (j, 101) {
      if (dp[i][j] == 0.0)
        continue;
      double pos = 1.0 * j / 100;
      ret += dp[i][j] * pos / 2;
      dp[i+1][max(0, j-q)] += dp[i][j] * pos / 2;
      ret += dp[i][j] * (1 - pos) / 3;
      if (i == 0)
        dp[i+1][p] += dp[i][j] * (1 - pos) / 3;
      else
        dp[i+1][min(100, j+q)] += dp[i][j] * (1 - pos) / 3;
    }
  }
  cout << fixed << setprecision(15) << ret << endl;

  return 0;
}