diff --git a/include/kernaux/pfa.h b/include/kernaux/pfa.h
index 47d42a0..5489c2c 100644
--- a/include/kernaux/pfa.h
+++ b/include/kernaux/pfa.h
@@ -22,6 +22,7 @@ struct KernAux_PFA_Zone {
     unsigned long long size;
 
     unsigned char pages[KERNAUX_PFA_ZONE_PAGE_LIST_SIZE];
+    unsigned int pages_count;
 };
 
 struct KernAux_PFA {