// #define _CRT_SECURE_NO_WARNINGS 
#include<stdio.h>
#include<math.h>

int t[1000][1000],n,m;
int max[3] = { 0 };
void sum(){
	
	for (int i = 0; i < pow((double)2, n);i++)
	for (int j = 0; j < pow((double)2, m); j++)
	{
		int s = 0;
		for (int k = 0; k < n; k++)
		for (int l = 0; l < m; l++)
		if ((((1 << k)&i) / (1 << k) + ((1 << l)&j) / (1 << l)) % 2){
			s -= t[k][l];

		}
		else{

			s += t[k][l];
		}
		if (s>max[0]){
			max[0] = s;
			max[1] = i;
			max[2] = j;
		}
	}
		printf("%d", max[0]);
}
int main(){
	freopen("flip.in", "r", stdin);
	freopen("flip.out", "w", stdout);
	scanf("%d%d", &n, &m);
	for (int i = 0; i < n;++i)
	for (int j = 0; j < m; ++j)
		scanf("%d", &t[i][j]);
	sum();
	return 1;
}