#include <stdlib.h>
#include <stdio.h>

int matrix_sum(int** matrix, int n, int m)
{
	int i, j, sum = 0;
	
	for (i = 0 ; i < n ; i++ )
		for (j = 0 ; j < m ; j++ )
			sum += matrix[i][j];
	return sum;
	
}

int flip_row(int** matrix, int n, int m, int sum, int r)
{
	int i;
	for (i = 0 ; i < m ; i++ )		
			sum -= 2 * matrix[r][i];
	return sum;	
}

int flip_col(int** matrix, int n, int m, int sum, int c)
{
	int i;	
	for (i = 0 ; i < n ; i++ )		
			sum -= 2 * matrix[i][c];
	return sum;	
}

int max (int a, int b)
{
	if (a > b)
		return a;
	return b;
}

int backtrack_col(int** matrix, int n, int m, int sum, int k)
{
	int i, tmp_sum, max_sum = sum;
	if (k == n - 1) {
		tmp_sum = flip_col(matrix, n, m, sum, m-1);
		max_sum = max(tmp_sum, max_sum);
	} else {
		for (i = k ; i < m ; i++ )
		{
			tmp_sum = flip_col(matrix, n, m, sum, i);
			max_sum = max(tmp_sum, max_sum);
			tmp_sum = backtrack_col(matrix, n, m, tmp_sum, i + 1);
			max_sum = max(tmp_sum, max_sum);
		}
	}
	return max_sum;
}

int backtrack (int** matrix, int n, int m, int sum, int k)
{
	int i, tmp_sum, max_sum = sum;
	if (k == n - 1) {
		tmp_sum = flip_row(matrix, n, m, sum, n-1);
		max_sum = max(tmp_sum, max_sum);
		
	} else {
		for (i = k ; i < n ; i++ )
		{			
			tmp_sum = flip_row(matrix, n, m, sum, i);
			max_sum = max(tmp_sum, max_sum);
			max_sum = max(backtrack_col(matrix, n, m, tmp_sum, 0), max_sum);
			tmp_sum = backtrack(matrix, n, m, tmp_sum, i + 1);
			max_sum = max(tmp_sum, max_sum);			
		}
	}
	return max_sum;
}

int main(int argc, char** argv)
{
	int n, m, i, j, sum;
	int **matrix;
	
	FILE *in, *out;
	
	in = fopen("flip.in", "r");
	out = fopen("flip.out", "w");
	
	fscanf(in, "%d %d", &n, &m);
	
	matrix = malloc( n * sizeof( int* ) );
	for (i = 0 ; i < n ; i++ )
		matrix[i] = malloc( m * sizeof( int ) );
	
	for (i = 0 ; i < n ; i++ )
		for (j = 0 ; j < m ; j++ )
			fscanf(in, "%d", &matrix[i][j]);
	
	sum = matrix_sum(matrix, n, m);
	
	sum = backtrack(matrix, n, m, sum, 0);
	
	printf("%d\n", sum);
	fprintf(out, "%d", sum);
	
	fclose(in);
	fclose(out);
}