import math
n=int(input())
p=float(input())
q=float(input())
if p==1:
  print(1)
elif q==1:
  print(0)
else:
  N=min(int((-5-math.log10(p))/(math.log10(p)+math.log10(q)))+1,n)
  ans=0
  for i in range(N+1):
    if i==0:
      ans+=p
    elif i==1:
      ans+=p**2*q
    else:
      C=math.factorial(2*i+2)//math.factorial(i+1)//math.factorial(i+1)
      ans+=C*q**i*p**(i+1)
  print(ans)