uva 11677 - Alarm Clock

n=1
	while n:
	data = [int(x) for x in input().split()]
	if data[0]==0 and data[1]==0 and data[2]==0 and data[3]==0:
	break
	if data[0]> data[2] or (data[0]==data[2] and data[1]>data[3]):
	time = (60-data[1]) + (23-data[0]+data[2])*60 + data[3]
	else:
	time = (60-data[1]) + (data[2]-data[0]-1)*60 + data[3]
	print(time)
	del data[:]