#include<stdio.h>
 FILE *f,*g;
 int n,m,a[17][17],i,j;
 long long s=0;
 int suma(){
     s=0;
     for(i=1;i<=n;i++){
         for(j=1;j<=m;j++){
             //fprintf(g,"%d ",a[i][j]);
             s+=a[i][j];
         }
         //fprintf(g,"\n");
     }
 }
  int main(){
      f=freopen("flip.in","rt",stdin);
      g=freopen("flip.out","wt",stdout);
      fscanf(f,"%d %d",&n,&m);
      for(i=1;i<=n;i++)
          for(j=1;j<=m;j++)
              fscanf(f,"%d",&a[i][j]);
              
      for(i=1;i<=n;i++){
          s=0;
          for(j=1;j<=m;j++)
              s+=a[i][j];
          if(s<-s)
              for(j=1;j<=m;j++) a[i][j]=-a[i][j];
      }
      for(j=1;j<=m;j++){
          s=0;
          for(i=1;i<=n;i++)
              s+=a[i][j];
          if(s<-s)
              for(i=1;i<=n;i++) a[i][j]=-a[i][j];
      }
      suma();
      fprintf(g,"%d",s);
      fclose(g);
      return 0;
  }