#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
ifstream fin ("flip.in");
ofstream fout ("flip.out");
int n, m, mt[20][20];
long long sum_neg, sum_pos, total_sum;

int main() {
    fin >> n >> m;
    for (int i = 1; i <= n; ++i) {
        sum_neg = 0, sum_pos = 0;
        for (int j = 1; j <= m; ++j) {
            fin >> mt[i][j];
            if (mt[i][j] < 0)
                sum_neg += mt[i][j];
            else
                sum_pos += mt[i][j];
        }
        if (abs(sum_neg) > sum_pos) {
            for (int j = 1; j <= m; ++j)
                mt[i][j] *= -1;
        }

    }
    for (int j = 1; j <= m; ++j) {
        sum_neg = 0, sum_pos = 0;
        for (int i = 1; i <= n; ++i) {
            if (mt[i][j] < 0)
                sum_neg += mt[i][j];
            else
                sum_pos += mt[i][j];
        }
        if (abs(sum_neg) > sum_pos)
            total_sum += abs(sum_neg) - sum_pos;
        else
            total_sum += sum_pos + sum_neg;
    }
    /*for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= m; ++j)
            cout << mt[i][j] << " ";
        cout << "\n";
    }*/
    fout << total_sum;
    return 0;
}