#include <bits/stdc++.h>

using namespace std;
ifstream fin("flip.in");
ofstream fout("flip.out");
int N, M, a[17][17];
unsigned long long s;
void Citire()
{
    fin>>N>>M;
    for(int i=1; i<=N; ++i)
        for(int j=1; j<=M; ++j)
        {
            fin>>a[i][j];
            a[i][0]+=a[i][j];
            a[0][j]+=a[i][j];
        }
    fin.close();
}
void Suma()
{
    for(int i=1; i<=N; ++i)
        if(a[i][0]<0)
            for(int j=1; j<=M; ++j)
                a[i][j]=-a[i][j];
    for(int j=1; j<=M; ++j)
        if(a[0][j]<0)
            for(int i=1; i<=N; ++i)
                a[i][j]=-a[i][j];
}
int main()
{
    Citire();
    Suma();
    for(int i=1; i<=N; ++i)
    {
        for(int j=1 ; j<=M; ++j)
            s+=a[i][j];
    }
    fout<<s;
    fout.close();
    return 0;
}