题解 | 绕距

import math

x1, y1 = map(int, input().split())
x2, y2 = map(int, input().split())

de = math.sqrt((x1 - x2)**2 + (y1 - y2)**2)

dm = abs(x1 - x2) + abs(y1 - y2)

detla = abs(dm - de)

print(f"{detla:.6f}")