#include<fstream>
using namespace std;
int n, m, i, j, k, maxim, sum, s;
int a[20][20], v[20], b[20][20];
ifstream fin("flip.in");
ofstream fout("flip.out");
int main(){
	fin>> n >> m;
	for(i = 1; i <= n; i++){
		for(j = 1; j <= m; j++){
			fin>> a[i][j];
		}
	}
	while(v[0] == 0){
		for(j = 1; j <= m; j++){
			if(v[j] == 0){
				for(i = 1; i <= n; i++){
					b[i][j] = a[i][j];
				}
			}
			else{
				for(i = 1; i <= n; i++){
					b[i][j] = -a[i][j];
				}
			}
		}
		sum = 0;
		for(i = 1; i <= n; i++){
			s = 0;
			for(j = 1; j <= m; j++){
				s += b[i][j];
			}
			if(s > 0){
				sum += s;
			}
			else{
				sum += (-s);
			}
		}
		if(sum > maxim){
			maxim = sum;
		}
		k = m;
		while(v[k] == 1){
			v[k] = 0;
			k--;
		}
		v[k] = 1;
	}
	fout<< maxim;
	return 0;
}