A little-known fact about cows is that they love puzzles! For Bessie's birthday, Farmer John gives her an interesting mechanical puzzle for her to solve. The puzzle consists of three solid objects, each of which is built from 1x1 unit squares glued together. Each of these objects is a "connected" shape, in the sense that you can get from one square on the object to any other square on the object by stepping north, south, east, or west, through squares on the object.

An object can be moved by repeatedly sliding it either north, south, east, or west one unit. The goal of the puzzle is to move the objects so that they are separated -- where their bounding boxes no longer share any positive overlap with each-other. Given the shapes and locations of the three objects, your task is to help Bessie decide what is the minimum number of individual slides required to separate the objects. (Figure omitted in this import.)

Line 1: Three space-separated integers: N1, N2, and N3, describing respectively the number of unit squares making up objects 1, 2, and 3.

Lines 2..1+N1: The (x,y) location of the south-west corner of each square of object 1 (coordinates in 0..9).

Lines 2+N1..1+N1+N2: Squares of object 2 (coordinates in 0..9).

Lines 2+N1+N2..1+N1+N2+N3: Squares of object 3 (coordinates in 0..9).

The minimum number of moves necessary to separate the three objects, or -1 if the objects cannot be separated.

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출처 올림피아드 > USACO > 2011-2012 > US Open > Silver