#include <iostream>
#include <fstream>
#define INF 1000000000
long long v[16][16];
int n, m;

using namespace std;

int main() {
	ifstream fi("flip.in");
	ofstream fo("flip.out");
	int i, j, k;
	fi >> n >> m;
	for (i = 0; i < n; i++) {
		for (j = 0; j < m; j++) {
			fi >> v[i][j]; 
		}
	}
	long long lim = 1 << (n + m);
	long long mx = -INF;
	long long s;
	for (k = 0; k < lim; k++) {
		s = 0;
		for (i = 0; i < n; i++) {
			for (j = 0; j < m; j++) {
				if ((k & (1 << i)) == (k & (1 << (n + j)))) {
					s += v[i][j];
				} else {
					s -= v[i][j];
				}
			}
		}
		if (s > mx)
			mx = s;
	}
	fo << mx;
	fi.close();
	fo.close();
	return 0;
}