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

public class Main {
    public static void main(String[] args) throws IOException {
        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();
        int maxSum = flip(n, m, board);
        PrintWriter pw = new PrintWriter("flip.out");
        pw.println(maxSum);
        pw.close();
    }

    public static int flip(int n, int m, int[][] board) {
        int maxSum = 0;
        for (int i = 0; i < (1 << n); i++) {
            for (int j = 0; j < (1 << m); j++) {
                int currSum = 0;
                for (int x = 0; x < n; x++) {
                    for (int y = 0; y < m; y++) {
                        if ((i & (1 << x)) != 0) {
                            board[x][y] *= -1;
                        }
                        if ((j & (1 << y)) != 0) {
                            board[x][y] *= -1;
                        }
                        currSum += board[x][y];
                    }
                }
                maxSum = Math.max(maxSum, currSum);
                for (int x = 0; x < n; x++) {
                    for (int y = 0; y < m; y++) {
                        if ((i & (1 << x)) != 0) {
                            board[x][y] *= -1;
                        }
                        if ((j & (1 << y)) != 0) {
                            board[x][y] *= -1;
                        }
                    }
                }
            }
        }
        return maxSum;
    }
}