import math

while(1):
    r = float(input('razdalja v m: '))
    swr = float(input('SWR: '))

    moc = ((swr-1.0)/(swr+1.0))**2
    rcs = (moc*4.0*math.pi*(4.0*math.pi*r**2)**2.0)/((55.0**2)*0.03**2)

    print(rcs)