#include "fstream"
#include "iostream"
using namespace std;
int main(){
	ifstream in;
	in.open("flip.in");
	if (in){
		ofstream out;
		out.open("flip.out");
		if (out){
			int n, m;
			in >> n;
			in >> m;
			int a[16][16];
			for (int i = 0; i < n; i++){
				for (int j = 0; j < m; j++){
					in >> a[i][j];
				}
			}
			int minl = 1000000, minc = 1000000,il,ic;
			int s = 0;
			for (int i = 0; i < n; i++){
				int sl = 0;
				for (int j = 0; j < m; j++){
					sl += a[i][j];
				}
				if (sl < minl){
					minl = sl;
					il = i;
				}
			}
			for (int i = 0; i < m; i++){
				int sc = 0;
				for (int j = 0; j < n; j++){
					sc += a[j][i];
				}
				if (sc < minc){
					minc = sc;
					ic = i;
				}
			}
			for (int i = 0; i < n; i++){
				for (int j = 0; j < m; j++){
					if (minl < 0 && minc < 0){
						if (i == il || j == ic){
							a[i][j] *= -1;
						}
					}
					else if (minc < 0){
						if (j == ic){
							a[i][j] *= -1;
						}
					}
					else if (minl < 0){
						if (i == il){
							a[i][j] *= -1;
						}
					}
					s += a[i][j];
				}
			}
			out << s;
		}
		in.close();
		out.close();
	}
	return 0;
}