P,C=map(int,raw_input().split())
V=[1]
for i in range(P):
    nextV=[]
    for p in (2,3,5,7,11,13):
        for v in V:
            nextV.append(v*p)
    V=nextV
for c in range(C):
    nextV=[]
    for p in (4,6,8,9,10,12):
        for v in V:
            nextV.append(v*p)
    V=nextV
print "%.9f"%(sum(V)/pow(6.0,C+P))