{
    using namespace RooFit;
    using namespace RooStats;
    
    RooRealVar n("n","observed yield",0.,50.);
    
    RooRealVar s("s","# of signal",1.,0.,10.);
    RooConstVar b("b","# of background",3.);
    RooAddition mean("mean","s+b",RooArgList(s,b));
    RooPoisson pois("pois","Poisson PDF",n, mean);
    
    RooDataSet data("data","data",RooArgSet(n));
    n.setVal(3);
    data.add(RooArgSet(n));
    
    RooWorkspace *wspace = new RooWorkspace("wspace");
    ModelConfig cfg(wspace);
    cfg.SetPdf(pois);
    cfg.SetParametersOfInterest(s);
    cfg.SetObservables(n);
    
    FeldmanCousins *fc = new FeldmanCousins(data,cfg);
    fc->SetConfidenceLevel(0.9);
    fc->UseAdaptiveSampling(true);
    fc->FluctuateNumDataEntries(false);
    fc->SetNBins(100);
    
    PointSetInterval* interval = fc->GetInterval();
    printf("F&C interval: [%.2f, %.2f]\n",interval->LowerLimit(s),interval->UpperLimit(s));
}