#include <iostream>
#include <algorithm>
#include <vector>
#include <stack>
#include <string>
#include <cmath>
#include <map>
#include <fstream>
#include <set>
#include <deque>

#define pb push_back
#define MAX 16

using namespace std;

int n, m;
int T[MAX][MAX];
int sol[16];
int ans = 0;

ifstream f("flip.in");
ofstream g("flip.out");

int sum() {
	int s = 0;
	for(int i = 0; i < n; i++) {
		int slin = 0;
		for(int j = 0; j < m; j++) slin += sol[j] * T[i][j];
		s += ((slin < 0) ? -1 : 1) * slin;  
	}
	return s;
}

void back(int k) {
	if(k == m) {
		ans = max(ans, sum());
		return;
	}

	sol[k] = 1; back(k+1);
	sol[k] = -1; back(k+1);
}

int main() {
	f >> n >> m;

	for(int i = 0; i < n; i++)
		for(int j = 0; j < m; j++)
			f >> T[i][j];

	back(0);

	g << ans;

	return 0;
}