#include <fstream>
#include <vector>
#include <algorithm>
#include <cstdlib>
#include <iostream>
using namespace std;
#define INFINITE 123456789
int fl[33], M, N;

long mat[17][17],sumamax;

void read () {
	fstream f;
	f.open("flip.in", fstream::in);
	f>>M>>N;
	for (int i=1; i<=M; i++)
		for (int j=1; j<=N;j++) {
			f>>mat[i][j];
			sumamax+=mat[i][j];
		}
	f.close();
}

long suma () {
	long s=0;
	for (int i=1; i<=M; i++)
		for (int j=1;j<=N;j++)
			s+=mat[i][j]*fl[i]*fl[M+j];
	return s;
}

int solution (int k) {
	return k==M+N;
}

void back(int k) {
	if (!solution(k)) {
		fl[k+1]=1;
		back(k+1);
		fl[k+1]=-1;
		back(k+1);
	} else {
		long s = suma();
		if (s > sumamax)
			sumamax=s;
	}
}
void solve () {
	fstream g;
	back(0);
	g.open("flip.out", fstream::out);
	g<<sumamax;
	g.close();
}
int main() {
	read();
	solve();
return 0;
}