diff --git a/src/algs/stogo/tools.cc b/src/algs/stogo/tools.cc
index ccc2139a..396a0bb0 100644
--- a/src/algs/stogo/tools.cc
+++ b/src/algs/stogo/tools.cc
@@ -161,9 +161,9 @@ bool TBox::CloseToMin(RVector &vec, double *objval, double eps_cl) {
   return FALSE;
 }
 
-unsigned int TBox::NStationary() {
+size_t TBox::NStationary() {
   // Returns the number of trials in a box
-  return TList.size() ;
+  return TList.size();
 }
 
 void TBox::split(RTBox B1, RTBox B2) {
diff --git a/src/algs/stogo/tools.h b/src/algs/stogo/tools.h
index 608ae9f6..f7eefeca 100644
--- a/src/algs/stogo/tools.h
+++ b/src/algs/stogo/tools.h
@@ -102,7 +102,7 @@ class TBox: public VBox {
   void ClearBox();            
   bool CloseToMin(RVector&, double*, double);
 
-  unsigned int NStationary();      // Returns the number of stationary points
+  size_t NStationary();      // Returns the number of stationary points
 
   void split(RTBox, RTBox);     // Split a box
   void dispTrials();