diff --git a/Reconstruction/Tracking/src/Clupatra/NNClusterer.h b/Reconstruction/Tracking/src/Clupatra/NNClusterer.h
index 2055d99c6fafbd1c55fc0618527de507300f6e36..990169c3b0d202e6ba4cecde6b7a5b67eb2b82b8 100644
--- a/Reconstruction/Tracking/src/Clupatra/NNClusterer.h
+++ b/Reconstruction/Tracking/src/Clupatra/NNClusterer.h
@@ -15,11 +15,11 @@
 namespace nnclu {
 
    /** fast check if integer is in a given range [Min,Max] */
-  template <unsigned Min,unsigned Max >
+  template <int Min, int Max >
   inline bool inRange( int i){   return ( (unsigned int) ( i - Min )  <= (unsigned int) ( Max - Min ) ); }
 
   /** fast check if integer is not in a given range [Min,Max] */
-  template <unsigned Min,unsigned Max >
+  template <int Min, int Max >
   inline bool notInRange( int i){   return ( (unsigned int) ( i - Min )  > (unsigned int) ( Max - Min ) ); }