#include<cstdio>
#include<algorithm>
#include<cstring>
#define Nmax 17
using namespace std;
int n,m,i,j,p,a[Nmax][Nmax],l,c,s,sol,S;
bool w[Nmax];
int main()
{
    freopen("flip.in","r",stdin);
    freopen("flip.out","w",stdout);
    scanf("%d %d",&n,&m);
    for (i=1;i<=n;i++)
    {
        s=0; S=0;
        for (j=1;j<=m;j++)
        scanf("%d",&a[i][j]),s+=a[i][j],S-=a[i][j];
        if (S>s) for (j=1;j<=m;j++) a[i][j]=-a[i][j];
    }
    for (i=0;i<=(1<<m)-1;i++)
    {
        s=0; memset(w,false,sizeof(w));
        for (j=0;1<<j<=i;j++)
        if (i&(1<<j)) w[j]=1;
        for (c=1;c<=n;c++)
        {
            if (w[c-1]==1)
            for (l=1;l<=n;l++) s-=a[l][c];
            else for (l=1;l<=n;l++) s+=a[l][c];
        }
        sol=max(s,sol);
    }
    printf("%d",sol);
    return 0;
}