#include <stdio.h>
int N,M,C[17][17],c[17][17],A[33],S,ST;


void citire()
{
FILE *F;
F=fopen("flip.in","r");
fscanf(F,"%d %d",&N,&M);
int i,j;
for(i=1;i<=N;i++)
	for(j=1;j<=M;j++)
	fscanf(F,"%d",&C[i][j]);
fclose(F);
}
void verificare()
{int i,j;
S=0;
for(i=1;i<=N;i++)
for(j=1;j<=M;j++)
c[i][j]=C[i][j];
for(i=1;i<=N;i++)
if (A[i]==1) for(j=1;j<=M;j++) c[i][j]=-c[i][j];
for(i=1;i<=M;i++)
if(A[i+16]==1) for(j=1;j<=N;j++) c[i][j]=-c[i][j];

for(i=1;i<=N;i++)
for(j=1;j<=M;j++)
S=S+c[i][j];
if(ST<S) ST=S;



}

void bkt(int k)
{int i;
if (k==34) verificare();
	else
	{
	for(i=0;i<=1;i++)
	A[k]=i;
	bkt(k+1);
	}
}



int main()
{
citire();
bkt(1);
FILE *G;
G=fopen("flip.out","w");
fprintf(G,"%d",ST);
fclose(G);
return 0;
}