import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;

public class Main {
       public static int flip(int[][] board, boolean[] row, boolean[] col, int i, int j, int sum) {
        if (i == board.length) {
            return sum;
        }
        int nexti = i, nextj = j + 1;
        if (nextj == board[0].length) {
            nexti++;
            nextj = 0;
        }
        int ans = flip(board, row, col, nexti, nextj, sum);
        if (i == 0 || j == 0 || row[i] || col[j]) {
            row[i] = !row[i];
            col[j] = !col[j];
            if (row[i]) {
                sum += 2 * board[i][j];
            } else {
                sum -= 2 * board[i][j];
            }
            ans = Math.max(ans, flip(board, row, col, nexti, nextj, sum));
            row[i] = !row[i];
            col[j] = !col[j];
            if (row[i]) {
                sum -= 2 * board[i][j];
            } else {
                sum += 2 * board[i][j];
            }
        }
        return ans;
    }

    public static void main(String[] args) throws IOException {
        // Read input
        BufferedReader br = new BufferedReader(new FileReader("flip.in"));
        String[] line = br.readLine().split(" ");
        int n = Integer.parseInt(line[0]);
        int m = Integer.parseInt(line[1]);
        int[][] board = new int[n][m];
        for (int i = 0; i < n; i++) {
            line = br.readLine().split(" ");
            for (int j = 0; j < m; j++) {
                board[i][j] = Integer.parseInt(line[j]);
            }
        }
        br.close();

        // Initialize row and col arrays to keep track of which rows and columns have been flipped
        boolean[] row = new boolean[n];
        boolean[] col = new boolean[m];

        // Call the flip function and get the maximum sum
        int maxSum = flip(board, row, col, 0, 0, 0);

        // Write output
        BufferedWriter bw = new BufferedWriter(new FileWriter("flip.out"));
        bw.write(Integer.toString(maxSum));
        bw.newLine();
        bw.close();
    }
}