package Abstraction;

import java.util.Scanner;

public class SequenceInMatrix {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int r = Integer.parseInt(scanner.next());
        int c = Integer.parseInt(scanner.next());

        String[][] arr = new String[r][c];
        for (int i = 0; i < r; i++) {
            for (int j = 0; j < c; j++) {
                arr[i][j] = scanner.next();
            }
        }
        int maxSequence = 0;
        int colmnSeq = -1;
        int rowSeq = -1;

        //Diagonals
        for (int i = 0; i < c; i++) {
            int crrSeq = CheckDiagonal(0,i,arr);
            if(crrSeq>=maxSequence){
                maxSequence=crrSeq;
                colmnSeq = i;
                rowSeq = 0;
            }
        }
        for (int i = 1; i < r; i++) {
            int crrSeq = CheckDiagonal(i,0,arr);
            if(crrSeq>=maxSequence){
                maxSequence=crrSeq;
                colmnSeq = 0;
                rowSeq = i;
            }
        }

        //Line
        for (int i = 0; i < r ;i++) {
            int crrSeq = CheckLine(i,arr);
            if(crrSeq>=maxSequence){
                maxSequence=crrSeq;
                colmnSeq = 0;
                rowSeq = i;
            }
        }

        //Columns
        for (int i = 0; i < c ;i++) {
            int crrSeq = CheckColumn(i,arr,c);
            if(crrSeq>=maxSequence){
                maxSequence=crrSeq;
                colmnSeq = i;
                rowSeq = 0;
            }
        }
        String repeating = arr[rowSeq][colmnSeq]+", ";
        String output = new String(new char[maxSequence-1]).replace("\0", repeating) + arr[rowSeq][colmnSeq];
        System.out.println(output);


    }

    private static int CheckDiagonal(int r, int c, String[][] arr) {
        String elm = arr[r][c];
        int count = 0;
        for (int i = 0; i+r < arr.length && i+c<arr[i+r].length; i++) {
            if(arr[i+r][i+c].equals(elm)){
                   count++;
            }
            else {
                break;
            }
        }
        return count;
    }
    private static int CheckLine(int r, String[][] arr) {
        String elm = arr[r][0];
        int count = 0;
        for (int i = 1; i< arr.length; i++) {
            if(arr[r][i].equals(elm)){
                count++;
            }else {
                break;
            }
        }
        return ++count;
    }
    private static int CheckColumn(int c, String[][] arr,int maxC) {
        String elm = arr[0][c];
        int count = 0;
        for (int i = 1; i< maxC; i++) {
            if(arr[i][c].equals(elm)){
                count++;
            }else {
                break;
            }
        }
        return ++count;
    }
}