#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
int main()
{
int n,m,i,j,maxi=0,a[17][17];
    long long c;
    long long x;
    FILE *f,*g;
    f=fopen("flip.in","r");
    g=fopen("flip.out","w");


     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]);





     c=1;
    x=1ll<<(n+m);
     while(c<x)
     {
         int S=0;
         int i,j;
         for(i=1;i<=n;i++)
            for(j=1;j<=m;j++)
            { //long long l=(c&(1ll<<(i-1)))>>(i-1);
            //long long b=(c&(1ll<<(n+j-1)))>>(n+j-1);
            long long r1,r2;
            r1=c&(1ll<<(i-1));
            r2=c&(1ll<<(j+n-1));
            if(r1&&r2||r1==0&&r2==0)
                S+=a[i][j];
            else
                S=S-a[i][j];


           // S+=(((-2)*((l+b)%2))+1)*a[i][j];
          // fprintf(g,"%d\n",S);

            //fprintf(g,"%lld %lld\n",l,b);
            }

            //fprintf(g,"%lld\n",c);
             c=c+1;
            // fprintf(g,"%d\n",S);

         if(S>maxi)
            maxi=S;


     }


 fprintf(g,"%d",maxi);


    return 0;
}