#include<stdio.h>
#define DIM 20
int n,m,a[DIM][DIM],s1,s2[DIM],s[DIM],p,i,j;
int main ()
{
    freopen("flip.in","r",stdin);
    freopen("flip.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(i=1;i<=n;++i)
        for(j=1;j<=m;++j)
        {
            scanf("%d",&a[i][j]);
            s[i]+=a[i][j];
        }
    for(j=1;j<m;++j)
        for(i=1;i<=n;++i)
            s2[j]+=a[i][j];
    for(j=1;j<=m;++j)
    {
        s1=0;
        for(i=1;i<=n;++i)
        s1+=(-1)*a[i][j];
        if(s1>s2[j])
        for(i=1;i<=n;++i)
        a[i][j]*=(-1);
    }       
    for(i=1;i<=n;++i)
    {
        s1=0;
        for(j=1;j<=m;++j)
        s1+=(-1)*a[i][j];
        if(s1>s[i])
        for(j=1;j<=m;++j)
        a[i][j]*=(-1);
    }
        
     for(i=1;i<=n;++i)
        for(j=1;j<=m;++j)
        p+=a[i][j];
        printf("%d",p);
        return 0;
    }