#include <iostream>
#include <vector>
#include <fstream>
//#include "A:\Programming_languages\C++\BasicUtils\BasicUtils\Utils.h";
using namespace std;
#define vi vector<int>
#define vvi vector<vector<int>>
vvi ReadTable(string location)
{
ifstream file(location, std::ios::in);
int lines, cols; //n = lines, m = cols
file >> lines >> cols;
vvi mat(lines);
for (int i = 0; i < lines; i++)
{
mat[i] = vi(cols);
for (int j = 0; j < cols; j++)
{
int ti;
file >> ti;
mat[i][j] = ti;
}
}
file.close();
return mat;
}
void FlipLine(vvi& mat, int line)
{
for (int i = 0; i < mat[line].size(); i++)
{
mat[line][i] *= -1;
}
}
void FlipCol(vvi& mat, int col)
{
for (int i = 0; i < mat.size(); i++)
{
mat[i][col] *= -1;
}
}
int Flip(vvi& mat)
{
//line flip
int lines = mat.size();
int cols = mat[0].size();
for (int i = 0; i < lines; i++)
{
int sum = 0;
for (int j = 0; j < cols; j++)
{
sum += mat[i][j];
}
if (sum < 0)
FlipLine(mat, i);
}
//col flip
for (int i = 0; i < cols; i++)
{
int sum = 0;
for (int j = 0; j < lines; j++)
{
sum += mat[j][i];
}
if (sum < 0)
FlipCol(mat, i);
}
int final_sum = 0;
for (int i = 0; i < lines; i++)
{
for (int j = 0; j < cols; j++)
{
final_sum += mat[i][j];
}
}
return final_sum;
}
int main()
{
ofstream result("flip.out", std::ios::out);
vvi mat = ReadTable("flip.in");
result << Flip(mat);
result.close();
return 0;
}