void plot_lrres(){
  double p[7]={0.5,1.0,1.5,2.0,2.5,3.0,3.5};
  // correct once
  double lr[7]={0.689,0.735,0.745,0.741,0.739,0.741,0.733};
  // correct twice, ref planes 0 and 0 
  double lr2[7]={0.729,0.771,0.779,0.782,0.782,0.787,0.776};
  // correct twice ref planes 2 and 0
  double lr3[7]={0.78,0.85,0.86,0.86,0.86,0.86,0.86};

  TH2F *hr13 = new TH2F("hr13","Left-right resolution",
                        2,0,4.,2,0,1);
  hr13->SetXTitle("p (GeV/c)");
  hr13->SetYTitle("Ratio of correctly corrected points/all points");
  hr13->Draw();

  TGraph *g0=new TGraph(7,p,lr3); 
  g0->SetMarkerStyle(kFullCircle);
  g0->SetMarkerColor(2);
  g0->SetLineColor(2);

  TGraph *g1=new TGraph(7,p,lr2); 
  g1->SetMarkerStyle(kOpenCircle);
  g1->SetMarkerColor(1);
  g1->SetLineColor(1);

  g0->Draw("p");
  g1->Draw("p"); 

  TLegend *legend=new TLegend(0.25,0.25,0.6,0.35);
  legend->AddEntry(g0,"Ref. planes 2 + 0","p");
  legend->AddEntry(g1,"Ref. planes 0 + 0","p");
  legend->Draw();

}