#include"stdio.h"
#include"stdint.h"
#define vrt 1
#define orz 2
void afis();
int_fast32_t mx[30][30],SUM_MAX=-200000,SUM;
int_fast16_t n,m,g,h,st[100];
bool mn[30][30];
void sum()
{
     long sum=0;
     for(int g=1;g<=m;g++)for(int h=1;h<=n;h++)
     {sum+=mx[h][g]*st[h+m]*st[g];
     }
     if(sum>SUM_MAX)SUM_MAX=sum;
}
void back(int k)
{
     if(k==n+m+1)sum();
     else
     {st[k]=-1;back(k+1);st[k]=1;back(k+1);}
}
int main()
{
     freopen("flip.in","r",stdin);freopen("flip.out","w",stdout);
     scanf("%d%d",&n,&m);
     for(g=1;g<=n;g++)for(h=1;h<=m;h++){scanf("%ld",&mx[g][h]);}
     back(1);
     printf("%ld",SUM_MAX);
     return 0;
}