#include "stdio.h"

int N, M;
int a[16][16];

int suma(int i, int j)
{
	int row, col;
	int suma = 0;
	for(row=0; row<N; row++)
		for(col=0; col<M; col++)
		{
			if(row==i)
				a[row][col] *= -1;
			if(col==j)
				a[row][col] *= -1;
			suma += a[row][col];
			if(row==i)
				a[row][col] *= -1;
			if(col==j)
				a[row][col] *= -1;
		}
	return suma;
}
int main(void)
{
	FILE *fin, *fout;
	
	int s, max;
	int i,j;
	if((fin = fopen("flip.in", "r"))==NULL)
		return -1;
	if((fout = fopen("flip.out", "w"))==NULL)
		return -1;
	fscanf(fin, "%d %d", &N, &M);
	for(i=0; i<N; i++)
		for(j=0; j<M; j++)
			fscanf(fin, "%d", &a[i][j]);
	for(i=0; i<N; i++)
	{
		for(j=0; j<M;j++)
		{
			s = suma(i, j);
			if(i==0 && j==0)
			{
				max = s;
			}
			else if(max<s)
			{
				max = s;
			}
		}
	}
	fprintf(fout, "%d\n", max);
	fclose(fin);
	fclose(fout);
	return 0;
}