#include<fstream>
using namespace std;
ifstream fin("flip.in");
ofstream fout("flip.out");
int n,m,a[20][20],v[20],maxim,sum,i,j,s,b[20][20];
int main(){
    maxim=-1;
    fin>>n>>m;
    for(i=1;i<=n;i++){
        for(j=1;j<=m;j++){
            fin>>a[i][j];
        }
    }
    while(v[0]==0){
        i=m;
        while(v[i]==1){
            v[i]=0;
            i--;
        }
        v[i]=1;

        //intoarcem coloanele ce corespund pozitiilor din v pe care este 1
        for(i=1;i<=n;i++){
            for(j=1;j<=m;j++){
                if(v[j]==1)
                    b[i][j]=-a[i][j];
                else
                    b[i][j]=a[i][j];
            }
        }
        sum=0;
        for(i=1;i<=n;i++){
            s=0;
            for(j=1;j<=m;j++){
                s=s+b[i][j];
            }
            if(s<0)
                sum-=s;
            else
                sum+=s;
        }
        if(sum>maxim)
            maxim=sum;
    }
    fout<<maxim;




    return 0;
}