#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <complex>
#include <queue>
#include <set>
#include <map>
#include <iomanip>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)

typedef long long ll;

int dice[] = {2,3,5,7,11,13,4,6,8,9,10,12};
int p, c;

double dfs(int idx, ll now, double prob) {
  if(idx == p+c) { return now * prob; }
  double sum = 0.0;
  rep(i, 6) {
    if(idx >= p) {
      sum += dfs(idx+1, now * dice[6+i], prob / 6.0);
    }
    else {
      sum += dfs(idx+1, now * dice[i], prob / 6.0);
    }
  }
  return sum;
}

int main() {

  cin >> p >> c;
  cout << setprecision(10) << dfs(0, 1, 1.0) << endl;

  return 0;
}