--- dsr-pdb-1.0.3/lib/PDB.cc	2005-11-02 14:27:11.000000000 -0800
+++ src/dsr-pdb-1.0.3/lib/PDB.cc	2008-09-03 09:50:07.000000000 -0700
@@ -82,7 +82,7 @@
     assert(i < models_.size());
     return models_[i];
   };
-  unsigned int PDB::number_of_models() const {
+  size_t PDB::number_of_models() const {
     return models_.size(); 
   }