a = input() x = ['', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'] s | C _Python_examples

a = input()
x = ['', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']
st1, num1, st2, num2 = x.index(a[0]), int(a[1]), x.index(a[3]), int(a[4])
if num1 < num2 and st1 < st2:
ans = ((num2 - num1) // 2 + (num2 - num1) % 2 + (st2 - st1) // 2 + (st2 - st1) % 2) // 2 + ((num2 - num1) // 2 + (num2 - num1) % 2 + (st2 - st1) // 2 + (st2 - st1) % 2) % 2
else:
ans = ((num1 - num2) // 2 + (num1 - num2) % 2 + (st1 - st2) // 2 + (st1 - st2) % 2) // 2 + ((num1 - num2) // 2 + (num1 - num2) % 2 + (st1 - st2) // 2 + (st1 - st2) % 2) % 2
print(ans)