a, b = map(int,input().split())
sec = (a * 60 + b) * 60

positionA = (sec % (3600*12)) / (3600 * 12) * 100
positionB = (sec % 3600) / 3600 * 100

minimum = 9999
minimumS = -1
addSec = 0
while True:
    addSec += 1

    positionA_next = ((sec + addSec) % (3600 * 12)) / (3600 * 12) * 100
    positionB_next = ((sec + addSec) % 3600) / 3600 * 100

    if (positionB <= positionA) and (positionB_next >= positionA_next):
        break

    positionA ,positionB = positionA_next, positionB_next

print(addSec-1)