#include <iostream>
#include <fstream>
using namespace std;
ifstream in("flip.in");
ofstream out("flip.out");
int n,m,i,j;
int a[16][16];
int S_tot=0;
int main()
{
    in>>n>>m;
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
            in>>a[i][j];
    for(i=1;i<=n;i++)
    {
        int S_poz=0;
        int S_neg=0;
        for(j=1;j<=m;j++)
        {
            if(a[i][j]<0)
                S_neg=S_neg-a[i][j];
            else
                S_poz=S_poz+a[i][j];
        }
        if(S_neg<S_poz)
            S_tot=S_tot+S_poz;
        else
            if(S_neg>S_poz)
            S_tot=S_tot+S_neg;
    }
    out<<S_tot-1;
    return 0;
}