#include <stdio.h>
#include <limits.h>
using namespace std;
FILE*f=fopen("flip.in","r"),
    *g=fopen("flip.out","w");
int m,n,i,j,ok,v[20],a[20][20];
long long s,s1;
int main()
{
    long long max;
    max=LONG_LONG_MIN;
    fscanf(f,"%d %d",&n,&m);
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
            fscanf(f,"%d",&a[i][j]);
    ok=1;
    while(ok==1){
        ok=0;
        for(i=1;i<=n;i++)
            if(v[i]==0){
                v[i]=1;
                ok=1;
                break;
            }
            else
                v[i]=0;
        if(ok==1){
            s=0;
            for(j=1;j<=m;j++){
                s1=0;
                for(i=1;i<=n;i++)
                    if(v[i]==1)
                        s1+=(a[i][j]*-1);
                    else
                        s1+=a[i][j];
                if(s1<0)
                    s+=(s1*-1);
                else
                    s+=s1;
                }

            if(s>max)
                max=s;
        }

    }
    fprintf(g,"%lld",max);
    return 0;
}