#include <stdio.h>
#include <stdlib.h>

FILE *f,*g;

int main()
{
    int N,M,a[16][16],s=0,s1=0,s2=0;

    f = fopen("flip.in","r");
    g = fopen("flip.out","w");

    fscanf(f,"%d",&N);
    fscanf(f,"%d",&M);
    
    for(int i=1; i<=N; i++)
        for(int j=1; j<=M; j++)
            fscanf(f,"%d",&a[i][j]);

    for(int i=1; i<=N; i++)
    {
        s1=0;
        s2=0;
        
       for(int j=1; j<=M; j++)
       {
            s1+=a[i][j];
            s2+=(-1)*a[i][j];
             
       } 

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

    for(int j=1; j<=M; j++)
    {
        s1=0;
        s2=0;
        
       for(int i=1; i<=N; i++)
       {
            s1+=a[i][j];
            s2+=(-1)*a[i][j];
             
       } 

       for(int i=1; i<=N; i++)
         if(s1<s2)
            a[i][j]=(-1)*a[i][j];  
    }

    for(int i=1; i<=N; i++)
       for(int j=1; j<=M; j++)
            s+=a[i][j];

    fprintf(g,"%d",s);

    /*for(int i=1; i<=N; i++)
     {
        for(int j=1; j<=M; j++)
            printf("%d ",a[i][j]);
        printf("\n");
     }*/

    fclose(f);
    fclose(g);

    return 0;
}