#include<fstream>
using namespace std;
int v[17][17];
int aux[17][17];
int ln[17];
int s, smax, n, m;
ofstream g("flip.out");
void suma()
{int i,j,col;
for(i=1;i<=n;i++)
if(ln[i] == -1)
for(j=1;j<=m;j++)
aux[i][j] = -v[i][j];
else
for(j=1;j<=m;j++)
aux[i][j] = v[i][j];
s=0;
for(j=1;j<=m;j++)
{
col = 0;
	for(i=1;i<=n;i++)
		col+=aux[i][j];
        if(col < 0) s-=col;
        else s+=col;
    }
    if(s>smax)  smax = s;}
void bkt(int p)
{
    if(p==n+1)
        suma();
    else
    {
ln[p] = 1;
        bkt(p+1);
        ln[p] = -1;
        bkt(p+1);
    }
}
 
int main() 
{ifstream f("flip.in");
int i,j;
f>>n>>m;
 for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
            f>>v[i][j];
 bkt(1);
 g<<smax;
 return 0;
}