#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;
         long long v[33];
         for(i=0;i<n+m;i++)
              v[i]=c&(1ll<<i);
        for(i=1;i<=n;i++)
            for(j=1;j<=m;j++)
            {
            if(v[i-1]&&v[n+j-1]||v[i-1]==0&&v[n+j-1]==0)
                S+=a[i][j];
            else
                S=S-a[i][j];
            }
             c=c+1;

         if(S>maxi)
            maxi=S;


     }


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


    return 0;
}