#include <stdlib.h>
#include <stdio.h>
#include <string.h>
//#include "Util.h"


int Sum(int **m, int row, int col)
{
    // Calculate the sum
    int s = 0;
    for(int i = 0; i < row; i++)
    {
        for(int j = 0; j < col; j++)
        {
            s += m[i][j];
        }
    }
    return s;
}

int main()
{
    FILE * m_pFileIn, * m_pFileOut;
    m_pFileIn = fopen ("flip.in","r");
    int row = 0, col = 0;
    // read row and col 
    fscanf(m_pFileIn, "%d %d", &row, &col);
    // read the elements
    int **m = (int**) malloc(sizeof(int*) * row);
    for( int i = 0; i < row; i++ )
    {
        m[i] = (int*)malloc(sizeof(int*)*col);
        for(int j = 0; j < col; j++)
        {
            fscanf(m_pFileIn, "%d", &m[i][j]);
        }
    }
     //Util::Print(m, row, col);
    
    int k = 0;
    while( k < 4 ) 
    {
        //cols 
        int *c1 = (int*)malloc(sizeof(int)*col);
        int *c2 = (int*)malloc(sizeof(int)*col);
        for(int j = 0; j < col; j++)
        {
            c1[j] = c2[j] = 0;
            for(int i = 0; i < row; i++)
            {
                c1[j] += m[i][j];
                c2[j] += (-1) * m[i][j];
            }
        }
        
        //Util::Print(m, row, col);
        for(int j = 0; j < col; j++)
        {
            if( c2[j] >= c1[j] )
            {
                //int s1 = Sum(m, row, col);
                for(int i = 0; i < row; i++)
                {
                    m[i][j] *= -1;
                }
               /* int s2 = Sum(m, row, col);
                if(s1 > s2 )
                {
                    for(int i = 0; i < row; i++)
                    {
                        m[i][j] *= -1;
                    }
                }*/
            }
        }
       // Util::Print(m, row, col);
    
        //rows
        int *r1 = (int*)malloc(sizeof(int)*row);
        int *r2 = (int*)malloc(sizeof(int)*row);
        for(int i = 0; i < row; i++)
        {
            r1[i] = r2[i] = 0;
            for(int j = 0; j < col; j++)
            {
                r1[i] += m[i][j];
                r2[i] += (-1) * m[i][j];
            }
        }
        //Util::Print(m, row, col);
        for(int i = 0; i < row; i++)
        {
            if(r2[i] >= r1[i])
            {
                //int s1 = Sum(m, row, col);
                for(int j = 0; j < col; j++)
                {
                    m[i][j] *= -1;
                }
               /* int s2 = Sum(m, row, col);
                if(s1 > s2 )
                {
                    for(int j = 0; j < col; j++)
                    {
                        m[i][j] *= -1;
                    }
                }*/
            }
        }
        //Util::Print(m, row, col);
        
        k++;
    }
    
    
    
    int s = Sum(m, row, col);
    printf("%d",s);
   
    
    m_pFileOut = fopen ("flip.out","w");
    fprintf(m_pFileOut, "%d", s);

    return 0;
}