#!/usr/bin/python
import random, sys

nCouples = int(sys.argv[1])
iters    = int(sys.argv[2])
tot = 0.0

for x in range(iters):
    nMales = nCouples
    nFemales = nCouples
    nSonlessCouples = nCouples
    while nSonlessCouples > 0:
        for i in range(nSonlessCouples):
            if random.randint(0,1)==1:
                # it's a boy! stop trying
                nMales = nMales + 1
                nSonlessCouples = nSonlessCouples - 1
            else:
                # it's a girl! try again
                nFemales = nFemales + 1
    tot += 1. * nFemales / (nMales + nFemales)
print tot/float(iters)