import sys
input=lambda: sys.stdin.readline().rstrip()
p,c=map(int,input().split())
P=[2,3,5,7,11,13]
C=[4,6,8,9,10,12]
n=p+c
N=6**n
ans=0
for i in range(N):
  cur=1
  for j in range(n):
    if j<p:
      cur*=P[i%6]
    else:
      cur*=C[i%6]
    i//=6
  ans+=cur/N
print(ans)