#include<iostream>
#include<fstream>
using namespace std;
void com2(long a[100][100],long j,int n)
{
    for (int i=1;i<=n;i++)
        a[i][j]=-1*a[i][j];
}
void com1(long a[100][100],long i,int m)
{
    for (int j=1;j<=m;j++)
        a[i][j]=-1*a[i][j];
}
int suma(long a[100][100],long n,long m)
{
    int s=0;
    for (int i=1;i<=n;i++)
        for (int j=1;j<=m;j++)
            s=s+a[i][j];
    return s;
}
int main()
{
    long a[100][100],n,maxim=0,s=0;
    int m,i,j;
    ifstream f("flip.in");
    ofstream g("flip.out");
    f>>n;
    f>>m;
    for (i=1;i<=n;i++)
        for (j=1;j<=m;j++)
        {
            f>>a[i][j];
            maxim=maxim+a[i][j];
        }
    f.close();
    for (i=1;i<=n;i++)
    {
        com1(a,i,m);
        if (suma(a,n,m)>maxim)
            maxim=suma(a,n,m);
        else
            com1(a,i,m);
    }
    for (j=1;j<=m;j++)
    {
        com2(a,j,n);
        if (suma(a,n,m)>maxim)
            maxim=suma(a,n,m);
        else
            com2(a,j,n);
    }
    g<<maxim;
    g.close();
    return 0;
}