SmallR is an archer. SmallR is taking a match of archer with Zanoes. They try to shoot in the target in turns, and SmallR shoots first. The probability of shooting the target each time is <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/a7487d7e62f90136b78ae3fbf0a008396f146e13.png" style="max-width: 100.0%;max-height: 100.0%;"/> for SmallR while <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/c443c7703e51f03d0eece0b96b9e84e425878209.png" style="max-width: 100.0%;max-height: 100.0%;"/> for Zanoes. The one who shoots in the target first should be the winner.

Output the probability that SmallR will win the match.
A single line contains four integers <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/488158367221f441ba94b9475c03436069df2a7e.png" style="max-width: 100.0%;max-height: 100.0%;"/>.
# 0.5*0.5+0.25*0.25+... = y+y^2+y^3+... (y=0.25) = y/1-y = .25/.75
# p=a/b,q=c/d,p'=1-p,q'=1-q
# pq'+p^2qq'+p^3q^2q'+... = pq'(1+pq+p^2q^2+...)=pq'/1-pq = a(d-c)/c(b-a)
a, b, c, d = map(int, input().split())
p = a / b
q = c / d
print((1 - p) / (1 - p * q))
