#include <iostream>
#include <fstream>
using namespace std;

int main()
{
ifstream f("flip.in");
ofstream g("flip.out");

int n,m,i,j;
long suma;

f>>n;
f>>m;

long s[n],a[n][m],v[m];
suma=0;

 for(i=1;i<=n;i++)
   {
    s[i]=0;
    for(j=1;j<=m;j++)
      {
          f>>a[i][j];
          s[i]=s[i]+a[i][j];
      }
      if (s[i]<0)
        for(j=1;j<=m;j++)
          a[i][j]=a[i][j]-2*a[i][j];
   }

   for (j=1;j<=m;j++)
   { v[j]=0;
      for (i=1;i<=n;i++)
        v[j]=v[j]+a[i][j];
     if (v[j]<0)
        suma=suma+v[j]-2*v[j];
     else suma=suma+v[j];
   }

   g<<suma;
   return 0;

}