#include <cstdio>

using namespace std;
int i,j,n,m,pas,ok,nr,s,max1,a[17][17],z,k,sum,s1,s2;
int main()
{
    freopen("flip.in","r",stdin);
    freopen("flip.out","w",stdout);
    pas=1;
    nr=1;
    max1=-999999;
    scanf("%d%d",&n,&m);
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
        {
            scanf("%d",&a[i][j]);
            s+=a[i][j];
        }
     for(k=1;k<=(1<<n);k++)
     {
         sum=0;
         for(j=1;j<=m;j++)
            {
                s1=0;
                s2=0;
                for(i=1;i<=n;i++)
         {
             if((1<<i)&k)
             z=a[i][j];
             else
                z=-a[i][j];
             if(z<0)
                s1+=z;
             else
                s2+=z;

         }
              if(-s1>s2)
              {
                  sum+=(-s1);
                  sum-=s2;
              }
              else
              {
                  sum+=s2;
                  sum+=s1;
              }
        }
        if(sum>max1)
            max1=sum;
     }
     printf("%d",max1);
    return 0;
}