Queen

The Problem

The game of Chess has several pieces with curious movements. One of them is the Queen, which can move any number of squares in any direction: in the same line, in the same column or in any of the diagonals, as illustrated by the figure below (black dots represent positions the queen may reach in one move):

The great Chess Master Kary Gasparov invented a new type of chess problem: given the position of a queen in an empty standard chess board (that is, an 8 x 8 board) how many moves are needed so that she reaches another given square in the board?

Kary found the solution for some of those problems, but is having a difficult time to solve some others, and therefore he has asked that you write a program to solve this type of problem.

The Input

The input contains several test cases. The only line of each test case contains four integers X₁, Y₁, X₂ and Y₂ (1 ≤ X₁, Y₁, X₂, Y₂ ≤ 8). The queen starts in the square with coordinates (X₁, Y₁), and must finish at the square with coordinates (X₂, Y₂). In the chessboard, columns are numbered from 1 to 8, from left ro right; lines are also numbered from 1 to 8, from top to bottom. The coordinates of a square in line X and column Y are (X, Y).

The end of input is indicated by a line containing four zeros, separated by spaces.

The Output

For each test case in the input your program must print a single line, containing an integer, indicating the smallest number of moves needed for the queen to reach the new position.

Sample Input

4 4 6 2
3 5 3 5
5 5 4 3
0 0 0 0

Sample Output

1
0
2

#include <stdio.h>
#include <stdlib.h>

int main() {
    int x, y, a, b;
    while(scanf("%d %d %d %d", &x, &y, &a, &b) == 4) {
        if(!x && !y && !a && !b)
            break;
        if(x == a && y == b)
            puts("0");
        else if(x == a || y == b || abs(x-a) == abs(y-b))
            puts("1");
        else
            puts("2");
    }
    return 0;
}