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x = int(input())
y = int(input())

if max(x, y) % 2 == 0 and max(x, y) - 1 == min(x, y):
    print(1)
elif max(x, y) % 4 == 0 and max(x, y) - 2 == min(x, y):
    print(2)
elif max(x, y) % 2 == 0 and max(x, y) - 5 == min(x, y):
    print(3)
elif max(x, y) % 2 == 1 and max(x,y) - 3 == min(x, y):
    print(3)
elif max(x,y) - 4 == min(x, y):
    print(3)
else:
    print(4)