#region Header
#!/usr/bin/env python3
# from typing import *

import sys
import io
import math
import collections
import decimal
import itertools
from queue import PriorityQueue
import bisect
import heapq

def input():
    return sys.stdin.readline()[:-1]

sys.setrecursionlimit(1000000)
#endregion

# _INPUT = """# paste here...
# """
# sys.stdin = io.StringIO(_INPUT)


def main():
    N = int(input())
    K = int(input())

    dp1 = [[0 for _ in range(6*N+1)] for _ in range(N+1)]
    dp1[0][0] = 1
    for n in range(1, N+1):
        for k in range(1, 6*N+1):
            dp1[n][k] = sum(dp1[n-1][max(k-6,0):k]) / 6

    dp2 = [[0 for _ in range(6*N+1)] for _ in range(N+1)]
    dp2[0][0] = 1
    for n in range(1, K+1):
        for k in range(1, 6*N+1):
            dp2[n][k] = sum(dp2[n-1][max(k-6,0):max(k-3,0)]) / 3
    for n in range(K+1, N+1):
        for k in range(1, 6*N+1):
            dp2[n][k] = sum(dp2[n-1][max(k-6,0):k]) / 6

    p = 0
    for k1 in range(1, 6*N+1):
        for k2 in range(k1+1, 6*N+1):
            p += dp1[N][k1] * dp2[N][k2]
    print(p)


if __name__ == '__main__':
    main()