a, b = map(int, input().split())
a = a if a < 12 else a - 12
x, ans = 30000, 0
for t in range(0, 3600):
    at = ((a * 5) + ((b * 60 + t) * 5 / 3600)) % 60
    bt = (b * 60 + t) * (1 / 60) % 60
    m = abs(at - bt)
    if x > m:
        x, ans = m, t
print(ans)