#include <fstream>
#include <iostream>
using std::cout;
int main()
{
    std::ifstream in("flip.in");
    std::ofstream out("flip.out");
    int n,m,tabla[16][16],sum1 = 0,sum2 = 0;
    in >> n >> m;
    for(int i = 0;i<n;i++)
    {
        sum1 = sum2 = 0;
        for(int j = 0;j<m;j++)
        {
            in >> tabla[i][j];
            sum1+=tabla[i][j];
            sum2-=tabla[i][j];
        }
        if(sum2 > sum1)
        for(int j = 0;j<m;j++)
        tabla[i][j]*=(-1);
    }
    in.close();
    for(int j = 0;j<m;j++)
    {
        sum1=sum2=0;
        for(int i = 0;i<n;i++)
        {
            sum1+=tabla[i][j];
            sum2-=tabla[i][j];
        }
        if(sum2 > sum1)
        for(int i = 0;i<n;i++)
        tabla[i][j]*=(-1);
    }
    sum1 = 0;
    for(int i = 0;i<n;i++)
    for(int j = 0;j<m;j++)
    sum1+=tabla[i][j];
    out << sum1;
    out.close();
    return 0;
}