#include<cstdio>

void bkt(int k);

int s1,s2,s,a[30][30],i,j,n,m,ss1,ss2,v[100],viz[100],mx,st;
int main()
{
    freopen("flip.in","r",stdin);
    freopen("flip.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
            scanf("%d",&a[i][j]);
    mx=-10000000;
    bkt(1);
    printf("%d",mx);
    return 0;
}

void bkt(int k)
{
    int i,j;
    st=0;
    for(j=1;j<=m;j++)
    {
        s=0;
        for(i=1;i<=n;i++)
        {
            if(viz[i]==0) s+=a[i][j];
            else s-=a[i][j];
        }
        if(s<0)
        {
            st-=s;
        }
        else st+=s;
    }
    if(mx<st) mx=st;
    for(i=v[k-1]+1;i<=n;i++)
    {
        v[k]=i;
        viz[i]=1;
        bkt(k+1);
        viz[i]=0;
    }
}