void root(){

TFile f("HLT_PTMultiplicity208.root");
//TFile f("HLT_PTMultiplicity208.root");

f.ls();

gDirectory->("demo");

f.cd ("demo");

f.ls();

TH1F *myHist=(TH1F*) gDirectory->Get("eta");

//myHist->Draw();

        for ( unsigned int i =0; i < myHist->GetNbinsX(); i++)
                  {
           cout<< myHist->GetBinContent(i);
           delta1=new TH1F("BinContent", "BinContent",100,0,100);
            delta1-> Fill (myHist->GetBinContent(i));


        }

}