{
gROOT->ProcessLine(".L markanal.C");
TFile* f=new TFile("markOutput.root");
TTree *mark  = (TTree*)f->Get("mark");
TTree *mark2 = (TTree*)f->Get("mark2");
markanal* a=new markanal(mark);
markanal* a2=new markanal(mark2);
   a->fChain->BuildIndex("number","another");
   a2->fChain->BuildIndex("number","another");
a->Loop(a2);
a2->Loop(a);
}