a,b = map(int, input().split())
ans = 0
if b < 23 or a > 25:
	ans = 3
elif 23 <= a and b <= 25:
	ans = 2 - (b - a)
elif a <= 23 and 23 <= b and b <= 25:
	ans = 25 - b
elif 23 <= a and a <= 25 and 25 <= b:
	ans = a - 23
print(ans)