from sys import stdin, stdout

def pBackStabber(P,Q):
    R = 100*P*Q/(P*Q+(100-P)*(100-Q))
    return "{0:.13f}".format(R)

P, Q = map(float, stdin.readline().replace("\n","").split(" "))
stdout.writelines("%s\n" % pBackStabber(P,Q))