#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)
     {
         float S=0;
         int i,j;
         for(i=1;i<=n;i++)
            for(j=1;j<=m;j++)
            S+=((-2)*((c&(1<<i))>>i+((c&(1<<(n+j)))>>(n+j))%2)+1)*a[i][j];
         c=c+1;
         if(S>maxi)
            maxi=S;


     }


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


    return 0;
}