#include<cstdio>
 
const int N=1<<5;
 
int a[N][N],v[N],b[N][N];
 
void baza2(int x)
{
    int nr=0;
    while (x)
    {
        nr++;
        v[nr]=x&1;
        x/=2;
    }
}
 
void init()
{
    for (int i=0;i<=16;i++)
        v[i]=0;
    for (int i=1;i<=16;i++)
        for (int j=1;j<=16;j++)
            a[i][j]=b[i][j];
}
 
int main()
{
    freopen("flip.in","r",stdin);
    freopen("flip.out","w",stdout);
    int n,m;
    scanf("%d%d",&n,&m);
    for (int i=1;i<=n;i++)
        for (int j=1;j<=m;j++)
        {
            scanf("%d",&a[i][j]);
            b[i][j]=a[i][j];
        }
    int x=1<<n,smax=1<<31;
    smax*=-1;
    for (int xx=0;xx<x;xx++)
    {
        baza2(xx);
        for (int i=1;i<=n;i++)
            if (v[i])
                for (int j=1;j<=m;j++)
                    a[i][j]*=-1;
        for (int j=1;j<=m;j++)
        {
            int ss=0;
            for (int i=1;i<=n;i++)
                ss+=a[i][j];
            if (ss<0)
                for (int i=1;i<=n;i++)
                    a[i][j]*=-1;
        }
        int s=0;
        for (int i=1;i<=n;i++)
            for (int j=1;j<=m;j++)
                s+=a[i][j];
        if (s>smax)
            smax=s;
        init();
        // vectorul v,modificam in functie de 0 si 1 coloanele matricei;
        // daca suma este negativa pe linie,modificam linia
    }
    printf("%d",smax);
    return 0;
}