#include<iostream>
#include<fstream>
using namespace std;
int flip[17][17],v[17];
int main()
{
	ifstream in("flip.in");
	ofstream out("flip.out");
	int m,n,i,j,k,max=0,s,s2,t;
	in>>n>>m;
	for(i=1;i<=n;++i)
		for(j=1;j<=m;++j)
        {
			in>>flip[i][j];
			max+=flip[i][j];
		}
	for(k=1;k<=((1<<m)-1);++k)
    {
		t=k;s2=0;
		for(j=1;j<=m;++j){
			v[j]=t%2;
			t/=2;
		}
		for(i=1;i<=n;++i){
			s=0;
			for(j=1;j<=m;++j){
				if(v[j]) s+=flip[i][j];
				else s-=flip[i][j];
			}
			if(s>0) s2+=s;
			else s2-=s;
		}
		if(s2>max) max=s2;
	}
	out<<max;
	return 0;
}