pi = 3.141592


def ro(d, m):

    p = (6 * m) / (pi * d ** 3)
    return p


def time(d, m):
    t = (15000*(3*m +5*pi*(d*d)*(5-d)))/(pi*(d*d))
    return t


Omg = []

for i in eval(input()):
    d, m = i
if ro(d, m) < 1000:
    Omg.append(time(d, m) * 60)
print(min(Omg))