#include<fstream>
using namespace std;
ifstream fin("flip.in");
ofstream fout("flip.out");
long a[20][20],i,m,n,s,j,s1,r,t;
int main(){
 fin>>n>>m;
 for(i=0;i<n;i++){
  for(j=0;j<m;j++){fin>>a[i][j];}
 }
 for(r=0;r<(1<<m);r++){s1=0;
  for(i=0;i<n;i++){
   for(t=0,j=0;j<m;j++){
    if(r&(1<<j)){t-=a[i][j];}
    else{t+=a[i][j];}
   }
   if(t>-t){s1+=t;}
   else{s1-=t;}
  }
  if(s1>s){s=s1;}
 }
 fout<<s;
 return 0;
}