#include <stdio.h>
#define fr(i,a,b) for(int i=a;i<b;++i)
#define N 16
int a[N][N];
int col[N];
int rows[N];
int n,m;
int maxsum;
void calc(){
    int sum=0;
    fr(i,0,m) col[i]=0;
    fr(i,0,n)fr(j,0,m) col[j]+=rows[i]?a[i][j]:-a[i][j];
    fr(i,0,m) sum+=col[i]>0?col[i]:-col[i];
    if(sum>maxsum)maxsum=sum;
    }
int backtrack(int d){
    if(d==n) calc();
    else{
        rows[d]=0;backtrack(d+1);
        rows[d]=1;backtrack(d+1);
        }
    }
int main(){
    freopen("flip.in","r",stdin);
    freopen("flip.out","w",stdout);
    scanf("%i%i",&n,&m);
    fr(i,0,n) fr(j,0,m)scanf("%i",a[i]+j);
    backtrack(0);
    printf("%i\n",maxsum);
    return 0;
    }