#include <bits/stdc++.h>
using namespace std;
ifstream fin("flip.in");
ofstream fout("flip.out");

void checksolution(int n, int m, int& summ, int elem[17][17], int rowncol[]) {
	int elements[17][17], s;

	s = 0;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++)
			elements[i][j] = elem[i][j];
	}
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			if (*(rowncol + i) == 1)
				elements[i][j] *= -1;
		}
	}
	for (int j = 0; j < m; j++) {
		for (int i = 0; i < n; i++) {
			if (*(rowncol + n + j) == 1)
				elements[i][j] *= -1;
		}
	}
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			s += elements[i][j];
		}
	}
	summ = max(s, summ);
}
void bkt(int niv, int n, int m, int rowncol[], int& summ, int elem[17][17]) {
	for (int i = 0; i < 2; i++) {
		rowncol[niv] = i;
		if (niv == n + m - 1)
			checksolution(n, m, summ, elem, rowncol);
		if(niv < n + m - 1)
			bkt(niv + 1, n, m, rowncol, summ, elem);
	}
}
int main() {
	int n, m, elements[17][17], rowncol[34], summ = INT_MIN;

	fin >> n >> m;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			fin >> elements[i][j];
		}
	}

	bkt(0, n, m, rowncol, summ, elements);
	fout << summ;

	fin.close();
	fout.close();
	return 0;
}