#include<fstream.h>
int main()
{
ifstream f("flip.in");
ofstream g("flip.out");
long a[30][30],b[30][30],smax=0,scol=0,stemp=0;
int n,m,st[20],k,j,i;
f>>n>>m;
for (i=1;i<=n;i++) for (j=1;j<=m;j++) {f>>a[i][j];smax+=a[i][j];}
k=1;
st[k]=-1;
while (k)
     {
     st[k]++;
     if (st[k]<=1) if (k==n)
		 {
		 for (i=1;i<=n;i++) for (j=1;j<=m;j++) if (st[i]) b[i][j]=-a[i][j];
						       else b[i][j]=a[i][j];
		 stemp=0;
		 for (j=1;j<=m;j++)
		    {
		    scol=0;
		    for (i=1;i<=n;i++) scol+=b[i][j];
		    if (scol<0) stemp=stemp+(-scol);
		    else stemp=stemp+scol;
		    }
		 if (stemp>smax) smax=stemp;
		 }
	       else
		 {
		 k++;
		 st[k]=-1;
		 }
     else k--;
     }
g<<smax;
f.close();
g.close();
return 0;
}