import numpy as np

x, t = list(map(int, input().split()))

print((max(x-t, 0)))
import numpy as np

x, t = list(map(int, input().split()))

print((np.max(np.array([x-t, 0]))))
import numpy as np

x, t = list(map(int, input().split()))
print((max(x - t, 0)))

import numpy as np

x, t = list(map(int, input().split()))
print((np.max(np.array([x - t, 0]))))

-print((max(x - t, 0))) +print((np.max(np.array([x - t, 0]))))