{
 TChain *c = new TChain("ntuple");
 c->Add("basic.root");
// c->Add("basic2.root");
 c->Draw("x:y");
 TCutG *cutg = new TCutG("cutg",4);
 cutg->SetPoint(0,0,0);
 cutg->SetPoint(1,1,0);
 cutg->SetPoint(2,1,1);
 cutg->SetPoint(3,0,1);
 c->Draw("x:y","cutg");

}