TASK

Problem

#96

Given two different chessboard squares `(x1,y1)` and `(x2,y2)`, print `YES` if a bishop can move from the first to the second in one legal move; otherwise print `NO`.

EXAMPLE

Example

Input

1 1 2 2

Output

YES

LIMITS

Constraints

1 ≤ x1, y1, x2, y2 ≤ 8; the two squares are different.

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LEARN Theory for this problem

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These exercises combine arithmetic, comparisons, and small branches. Keep each condition explicit and easy to verify.

Connection to “Chess Bishop Move”: here, intermediate values are best kept in named variables so the formula stays readable and data types remain clear.

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NEED HELP? Hints

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['Break the task into a few simple checks instead of compressing everything into a clever expression.', 'After solving “Chess Bishop Move”, verify the algorithm on your own small example and on an allowed boundary case. Print only the required result with no extra text.']

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ANSWER Solution

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#include <iostream>
#include <algorithm>
#include <cstdlib>
using namespace std;
int main() {
    long long x1,y1,x2,y2;
    cin >> x1 >> y1 >> x2 >> y2;
    cout << ((llabs(x1-x2)==llabs(y1-y2))?"YES":"NO") << '\n';
    return 0;
}