#include<stdio.h>
#define MAX 100
int sol[MAX],mx;
 
int suma()  {
    int ax, rez = 0;
    for (int i = 1 ; i <= n ; i++)    {
        ax = 0;
        for (int j = 1 ; j <= m ; j++)
            ax += sol[j] ? (- M[i][j]) : M[i][j];
        if (ax < 0)
            ax = -ax;
        rez += ax;
   }
    return rez;
}
 
void intoarce (int k)   {
    int x;
    if (k == m + 1)
        x = suma(), mx = x > mx ? x : mx;
    else  {
        for (int i = 0 ; i < 2 ; i++)   {
            sol[k] = i;
            back(k + 1);
        }
    }
}


int main(){
    int a,b,i;
    int
    FILE *in=fopen("flip.in","r");
    FILE *out=fopen("flip.out","w");
    fscanf(in,"%d %d\n",&a,&b);
    if ( a<=1 && b>= 16)
       return 1;
    for (i=0;i<a;i++)
        for (j=0;j<b;j++)
            fscanf(in,"%d",&m[a][b]);
    intoarce(1);
    fprintf(out,"%d",mx);                       
return 0;
}