#include<fstream>
using namespace std;
long long v[20][20],s1[20],s;
int main()
{int i,j,m,n,x;
    ifstream fin("flip.in");
ofstream fout("flip.out");
fin>>n>>m;
for(i=1;i<=n;i++)
{s=0;
for(j=1;j<=m;j++)
{fin>>v[i][j];s+=v[i][j];s1[j]+=v[i][j];}
if(s<0)v[i][0]=1;
}
for(i=1;i<=m;i++)
if(s1[i]<0)v[0][i]=1;
s=0;
for(i=1;i<=n;i++)
for(j=1;j<=m;j++)
if(v[i][0]==v[0][j])
s+=v[i][j];
else
s-=v[i][j];
fout<<s;
fin.close();
fout.close();
return 0;
    
    }