#include<iostream>
#include<fstream>
using namespace std;

ifstream fin("flip.in");
ofstream fout("flip.out");

int a[100][100],n,m,suma,suma_total;
int calcul(){
	int aux;
	suma=0;
	for(int i=1;i<=n;++i){
		aux=0;
		for(int j=1;j<=m;++j){
			aux+=a[i][j];
		}
		if(aux<0){
			aux*=(-1);
		}
		suma+=aux;
	}
}
int bt(int k){
	if(k>m){
		calcul();
		suma_total=max(suma_total,suma);
	}else{
		bt(k+1);
		for(int i=1;i<=n;++i)
			a[i][k]*=(-1);
		bt(k+1);	
	}
}
int main(){
	fin>>n>>m;
	for(int i=1;i<=n;++i)
		for(int j=1;j<=m;++j)
			fin>>a[i][j];
	bt(1);
	fout<<suma_total;
	fin.close();
	fout.close();
	
}