#include<cstdio>
#include<cmath>
#include<algorithm>
using namespace std;
FILE *fin=fopen("flip.in","r");
FILE *fout=fopen("flip.out","w");

int ma[17][17],n,m,i,j,v[17],w,aux,gata,stotal,smax,s,final;
int main()
{
    fscanf(fin,"%d%d",&n,&m);
    for(i=1;i<=n;i++)
    for(j=1;j<=m;j++)
    fscanf(fin,"%d",&ma[i][j]);
    final=1;
    for(i=1;i<m;i++)
    final*=2;
    v[1]=-1;
    for(w=1;w<=final;j++)
    {
        v[1]++;
        for(i=1;i<=m&&v[i]==2;i++)
            v[i]=0,v[i+1]=1;
        for(i=1;i<=m;i++)
            if(v[i]==1)
            {
                for(j=1;j<=n;j++)
                ma[j][i]*=(-1);
            }
        stotal=0;
        for(i=1;i<=n;i++)
        {
            s=0;
            for(j=1;j<=m;j++)
            s+=ma[i][j];
            stotal=max(s,s*(-1));
        }
        if(stotal>smax)
        smax=stotal;
    }
    fprintf(fout,"%d",stotal);
    return 0;
}