diff --git a/analysis/PWGC2F/femtoscopy/nicafemto/format/unigen/NicaUnigenSource.cxx b/analysis/PWGC2F/femtoscopy/nicafemto/format/unigen/NicaUnigenSource.cxx
index f9597e4d76dfcb2dd0f3a0d06e6f0876ad72836e..d6b9e5bf1bad9be77dc6b2ad57800f9ff17e711f 100644
--- a/analysis/PWGC2F/femtoscopy/nicafemto/format/unigen/NicaUnigenSource.cxx
+++ b/analysis/PWGC2F/femtoscopy/nicafemto/format/unigen/NicaUnigenSource.cxx
@@ -13,6 +13,7 @@
 #include "UParticle.h"
 #include <TBranch.h>
 #include <fstream>
+#include <iostream>
 
 NicaUnigenSource::NicaUnigenSource()
   : fUnigenChain(NULL), fFileName("data.root"), fEvent(NULL) {}