#!/usr/bin/env python3
import re

lines = (x.strip() for x in open("input.txt"))
# all lines of possible positions
# mx+b; tl/br have m=1; tr/bl have m=-1
tl, tr, bl, br = set(), set(), set(), set()
stations = []

for line in lines:
    x, y, bx, by = map(int, re.search(r"(-?\d+).+?(-?\d+).+?(-?\d+).+?(-?\d+)", line).groups())
    dist = abs(x-bx) + abs(y-by) + 1
    tl.add(y-dist+x)
    br.add(y+dist+x)
    bl.add(y+dist-x)
    tr.add(y-dist-x)
    stations.append((x, y, dist))

for bu, bd in ((a, b) for a in tl & br for b in tr & bl):
    # -x+bu=x+bd <=> x=(bd-bu)/2
    x = (bu-bd)//2
    y = x+bd

    if all(abs(x-sx)+abs(y-sy) >= dist for sx, sy, dist in stations):
        print(x*4000000+y)