#include<bits/stdc++.h>
typedef unsigned long long ull;
using namespace std;
int a[16][16],m,n,ans;
ifstream fin("flip.in");
ofstream fout("flip.out");
int main()
{
ull i,j,s,r,t;
fin>>n;
fin>>m ;
for (i=0;i<n;i++)
for (j=0;j<m;j++)fin>>a[i][j];
for (r=0;r<(1<<m);r++)  {ans=0;
                            for (i=0;i<n;i++){
                                                for (t=j=0;j<m;j++)    if (r&(1<<j))t+=-a[i][j];
                                                                                else t+=a[i][j];
                                                if (t>-t)s+=t;
                                                else s+=-t;}
                                                if (s>ans)ans=s;}
fout <<ans;
return 0;
}