TH2D *getZeroMask(TH2D *input)
{
	TH2D *result = new TH2D("zeromask","",input->GetNbinsX(), 0,1,input->GetNbinsY(),0,1);
	Double_t maxVal = input->GetMaximum();
	Double_t minVal = input->GetMinimum() - 1.0;
	for (Int_t i = 0; i < input->GetNcells(); ++i) {
		if (input->GetBinContent(i) == 0.0) {
			result->SetBinContent(i,maxVal);
		} else {
			result->SetBinContent(i,minVal);
		}
	}
	return result;
}