#include <iostream>
#include <fstream>


using namespace std;


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


int main()
{
	int v[101][101];
	int N, M, sum=0;
	fin >> N >> M;
	for (int i = 1; i <= N; i++)
		for (int j = 1; j <= M; j++)
			fin >> v[i][j];

	for (int i = 1; i <= N; i++)
	{
		int s1 = 0, s2 = 0;
		for (int j = 1; j <= M; j++)
			s1 += v[i][j];

		for (int j = 1; j <= M; j++)
			v[i][j] = v[i][j] * (-1);

		for (int j = 1; j <= M; j++)
			s2 += v[i][j];

		if (s1 > s2)
		{
			for (int j = 1; j <= M; j++)
				v[i][j] = v[i][j] * (-1);
		}
	}

	for(int j=1;j<=M;j++)
    {
        int s1=0, s2=0;
        for(int i=1;i<=N;i++)
            s1+=v[i][j];

        for(int i=1;i<=N;i++)
            v[i][j]=v[i][j]*(-1);

        for(int i=1;i<=N;i++)
            s2+=v[i][j];

        if(s1>s2)
        {
            for(int i=1;i<=N;i++)
                v[i][j]=v[i][j]*(-1);
        }
    }
    for(int i=1;i<=N;i++)
    {
        for(int j=1;j<=M;j++)
            sum+=v[i][j];
    }
    fout<<sum;
    /*
	for (int i = 1; i <= N; i++)
    {
		for (int j = 1; j <= M; j++)
        {
			cout << v[i][j]<<" ";
        }
        cout<<endl;
    }
    */
    fin.close();
    fout.close();
	return 0;
}