package main

import (
	"bufio"
	"fmt"
	"math"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func main() {
	sc.Split(bufio.ScanWords)
	seq := make([]int64, 0, 100)
	seq = append(seq, 1)
	p, c := nextInt(), nextInt()
	pt, ct := []int64{2, 3, 5, 7, 11, 13}, []int64{4, 6, 8, 9, 10, 12}

	for i := 0; i < p; i++ {
		subSeq := make([]int64, 0, 10000)
		for _, v := range seq {
			for _, v2 := range pt {
				subSeq = append(subSeq, v*v2)
			}
		}
		seq = subSeq
	}

	for i := 0; i < c; i++ {
		subSeq := make([]int64, 0, 10000)
		for _, v := range seq {
			for _, v2 := range ct {
				subSeq = append(subSeq, v*v2)
			}
		}
		seq = subSeq
	}
	t := int64(0)
	for _, v := range seq {
		t += v
	}
	fmt.Println(float64(t) / math.Pow(float64(6), float64(p+c)))
}

func nextLine() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	i, _ := strconv.Atoi(nextLine())
	return i
}

func nextInt64() int64 {
	i, _ := strconv.ParseInt(nextLine(), 10, 64)
	return i
}

func nextUint64() uint64 {
	i, _ := strconv.ParseUint(nextLine(), 10, 64)
	return i
}

func nextFloat() float64 {
	f, _ := strconv.ParseFloat(nextLine(), 64)
	return f
}