{
   gROOT->SetStyle("Plain");
   TCanvas tc("c1","c1",0,0,600,500);

   TFile *tf=TFile::Open("collimspec.root");
   h100->SetLineWidth(2);
   gStyle->SetOptStat(0);
   gStyle->SetOptTitle(0);
   h100->GetXaxis()->SetRangeUser(5.,12.);
   h100->GetYaxis()->SetRangeUser(0.,5.e8);
   h100->GetXaxis()->SetTitle("E_{#gamma} (GeV)");
   h100->GetYaxis()->SetTitle("beam spectral intensity (/GeV/s)");
   h100->GetYaxis()->SetTitleOffset(1.6);
   h100->Draw("c");

   h200->SetLineWidth(2);
   h200->SetLineColor(2);
   h200->Clone("h400");
   h400->Add(h300,-1);
   h400->SetLineColor(3);
   h400->Draw("csame");
   h200->Draw("csame");
}