#include<fstream>
using namespace std;
long long n,m,st,s,smax,i,j,v[18],a[17][17];
ifstream f("flip.in");
ofstream g("flip.out");
long long addup()
{long long s=0;
for (int i=1;i<=m;i++){long long st=0;
for (int j=1;j<=n;j++)
st+=v[j]*a[i][j];
if (st>=0)
s+=st;
else s-=st;}
return s;
}
void backs(int x)
{if (x==m)
{long long s;
s=addup();
if (s>smax)
smax=s;
}
else
{v[x]=1;
backs(x+1);
v[x]=-1;
backs(x+1);
}
}
int main()
{f>>m>>n;
for (i=1;i<=m;i++)
for (j=1;j<=n;j++)
f>>a[i][j];
for (i=1;i<=18;i++)
v[i]=1;
backs(0);
g<<smax<<'\n';
return 0;
}