#include<stdio.h>
int k,s,max,l,n,m,i,j,k2,l2;
int a[17][17];
int b[17][17];
int v[200][20],t[200][20];


int main(){
  FILE *f=fopen("flip.in","r");

 fscanf(f,"%d",&n);
 fscanf(f,"%d",&m);

 for(i=1;i<=n;i++){
    for(j=1;j<=m;j++){
    fscanf(f,"%d",&a[i][j]);
    }
 }

 max=0;

fclose(f);

 for(k=0;k<=(1<<m)-1;k++){

    for(l=m-1;l>=0;l--){

    v[k+1][l+1]=(k>>l)&1;
    }
}



  for(k=0;k<=(1<<n)-1;k++){

    for(l=n-1;l>=0;l--){

    t[k+1][l+1]=(k>>l)&1;
    }
  }



 for(k=1;k<=(1<<m);k++){

   for(k2=1;k2<=(1<<n);k2++){

      for(j=1;j<=m;j++){

       if(v[k][j]==1)

	 for(i=1;i<=n;i++) b[i][j]=(-1)*a[i][j];

       else  for(i=1;i<=n;i++) b[i][j]=a[i][j];

     }

     s=0;

	for(i=1;i<=n;i++){

	 if(t[k2][i]==1){

	   for(j=1;j<=m;j++){b[i][j]/=(-1);s+=b[i][j];}

	 }

	 else for(j=1;j<=m;j++){s+=b[i][j];}

	}




    // s=0;

     //for(i=1;i<=n;i++){
      //	for(j=1;j<=m;j++){
       //	s=s+c[i][j];
	//}
    // }

    if(s>max){max=s;}

   }

 }

 FILE *g=fopen("flip.out","w");
 fprintf(g,"%d\n",max);
 fclose(g);

return 0;
}