local a, b = io.read("*n", "*n")
if 12 <= a then a = a - 12 end
-- a_ang = 30 * a + 0.5 * b
-- b_ang = 6 * b
local a_ang2 = 60 * a + b
local b_ang2 = 12 * b
local diff = a_ang2 - b_ang2
if diff < 0 then diff = diff + 720 end
-- b_speed = 720/3600 = 0.2
-- a_speed = b_speed / 12
-- diff_speed = 11 / 60
-- ans = diff / diff_speed
--     = diff * 60 / 11
print(math.floor(diff * 60 / 11))