void droop() {
  gROOT->SetStyle("Plain");

  TCanvas *c1=new TCanvas("c1","Canvas",800,600);
  gStyle->SetOptStat(0);
  gStyle->SetPalette(1);
  //gStyle->SetPadLeftMargin(0.12);
  //gStyle->SetPadRightMargin(0.12);
  //c1->UseCurrentStyle();

  TGraph *tg[43];
  for(unsigned i(0);i<43;i++) {
    tg[i]=new TGraph(20);
    tg[i]->SetMarkerStyle(20);
    //tg[i]->SetMarkerColor(i);
    //tg[i]->SetLineColor(i);
    if(i==0) {
      tg[i]->SetMarkerColor(2);
      tg[i]->SetLineColor(2);
    } else {
      tg[i]->SetMarkerColor(4);
      tg[i]->SetLineColor(4);
    }
    tg[i]->SetLineWidth(2);
  }

  ifstream fin("droop.txt");

  unsigned ch;
  double p,s;

  for(unsigned i(0);i<86;i++) {
    fin >> ch;
    cout << " " << ch;
    //if(ch!=0) cout << i << " " << ch << endl;
    if((i%10)==9) cout << endl;
  }

  for(unsigned j(0);j<20;j++) {
    fin >> ch;
    cout << "N = " << 42*ch;
    fin >> ch;
    cout << ", run = " << ch << endl;
    
    for(unsigned i(0);i<43;i++) {
      fin >> p >> s;
      tg[i]->SetPoint(j,42*(j+1),s);
      //cout << i << ", ped = " << p << ", sigma = " << s << endl;
    }
  }

  tg[1]->SetTitle(";Number of unmasked pixels;Pixel noise (DTU)");
  tg[1]->GetYaxis()->SetRangeUser(0,30);
  tg[1]->GetXaxis()->SetRangeUser(0,900);
  tg[1]->Draw("AL");
  for(unsigned i(2);i<16;i++) {
    tg[i]->Draw("Lsame");
  }
  tg[0]->Draw("Lsame");

  c1->Update();
  c1->Print("../droop.png");
}