#define _USE_MATH_DEFINES
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include <sstream>
#include<iomanip>

//#include<bits/stdc++.h>


using namespace std;

int main() {
	int n, k;
	cin >> n >> k;
	int s = 0, i = 0, j = 0, t;
	for (i = 0; i < 4000000;i++) {
		t = 0;
		for (j = 0; j < k; j++)t += rand() % 3 + 4;
		for (; j < n; j++)t += rand() % 6 + 1;
		for (j = 0; j < n; j++)t -= rand() % 6 + 1;
		if (t > 0)s++;

	}
	cout << (double)s / 4000000 << endl;

	return 0;
}