#include<fstream.h>
main()
{
fstream f("C:\\flip\\flip.in",ios::in),g("C:\\flip\\flip.out",ios::out);
int S=0,i,j,N,M,v[100][100],min,ok=0;
f>>N>>M;
for(i=1;i<=N;i++)
	{
	j=1;
	f>>v[i][j];
	if(v[i][j]<0)
		v[i][j]*=-1;
	min=v[i][j];
	for(j=2;j<=M;j++)
		{
		f>>v[i][j];
		if(v[i][j]<0)
			v[i][j]*=-1;
		if(v[i][j]<min)
			min=v[i][j];
		}
	for(j=1;j<=M;j++)
		{
		if((v[i][j]==min)&&(ok!=1))
			{
			v[i][j]*=-1;
			ok++;
			}
		S+=v[i][j];
		}
	ok=0;
	cout<<endl;
	}
g<<S;
f.close();g.close();
}