RoundD2021ArithmeticSquare.java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;
//https://codingcompetitions.withgoogle.com/kickstart/round/00000000004361e3/000000000082b813 
import java.util.*;

public class RoundD2021ArithmeticSquare {

    public static void main(String[] args) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(br.readLine());
        ArrayList mat = new ArrayList(new ArrayList());
        mat.add(new ArrayList(Arrays.asList(br.readLine().split(" "))));
        mat.add(new ArrayList(Arrays.asList(br.readLine().split(" "))));
        mat.add(new ArrayList(Arrays.asList(br.readLine().split(" "))));

    }
    // n(a+l)/2 = sum of ap
}