#include <fstream>

using namespace std;

ifstream in("flip.in");
ofstream out("flip.out");

int main()
{
    int randuri, coloane;
    int i,j;
    int sum=0,sum_s;

    in>>coloane>>randuri;

    int tabla[randuri][coloane];

    for(i=0;i<randuri;++i)
    {
        sum_s=0;

        for(j=0;j<coloane;++j)
        {
            in>>tabla[i][j];
            sum_s+=tabla[i][j];
        }

        if(sum_s*(-1)>sum_s)
            sum-=sum_s;
        else
            sum+=sum_s;
    }

    for(i=0;i<coloane;++i)
    {
        sum_s=0;

        for(j=0;j<randuri;++j)
            sum_s+=tabla[j][i];

        if(sum_s*(-1)>sum_s)
            sum-=2*sum_s;
    }

    out<<sum;

    return 0;
}