A, B = map(int, input().split())

x = 12 * 60 * 60 / 11
t = (A * 60 + B) * 60 % (12 * 60 * 60)

if t / x - int(t / x) < 0.001:
    print(0)
    exit()

y = int(t / x)

for i in range(int(x) + 1):
    z = int((t + i) / x)
    if y != z:
        print(i - 1)
        exit()