#include <iostream>
#include <fstream>
using namespace std;
int a[18][18];
int sum;
void r(int x[], int k, int m, int n)
{
    int i,j,S=0,s;
    for(i=1;i<=n;i++)
    {
        s=0;
        for(j=1;j<=m;j++)
        {
            if(x[j])
                s-=a[i][j];
            else
                s+=a[i][j];
        }
        if(s<0)
            S+=-s;
        else
            S+=s;
    }
    if(S>sum)
        sum=S;
}
int main()
{

    int n,m,i,j,x[20],k;
    fstream f,g;
    f.open("flip.in",ios::in);
    g.open("flip.out",ios::out);
    f>>n>>m;
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
        {
            f>>a[i][j];
            sum+=a[i][j];
        }
    k=1;
    x[k]=-1;

    while(k)
    {

        while(x[k]<1)
        {
            x[k]++;
            if(k==m)
                r(x,k,m,n);
            else
                x[++k]=-1;
        }
        k--;
    }
    g<<sum;


}