{
leg = new TLegend(0.7,0.7,0.9,0.9,"exercise 3");
TFile *f = new TFile("ex03_e.root");
leg->AddEntry(shower,"1 GeV electron","l");
shower->Draw();
TFile *f = new TFile("ex03_pion.root");
shower->SetLineColor(2);
leg->AddEntry(shower,"1 GeV pion","l");
shower->Draw("SAME");
leg->SetBorderSize(0);
leg->SetFillColor(10);
leg->Draw();
c1->Print("shower.png");
}