diff --git a/src/observersmanager.hpp b/src/observersmanager.hpp
index 38a6934..680c571 100644
--- a/src/observersmanager.hpp
+++ b/src/observersmanager.hpp
@@ -136,9 +136,14 @@ namespace cloonel {
 		m_occupied[parTicket - 1] = false;
 		--m_usedCount;
 
-		auto lastNull = std::find(m_occupied.rbegin(), m_occupied.rend(), false);
-		if (m_occupied.rend() != lastNull) {
-			const std::size_t newSize = m_occupied.size() - static_cast<std::size_t>(lastNull - m_occupied.rbegin()) + 1;
+		std::size_t deleCount = 0;
+		for (auto itOcc = m_occupied.rbegin(), itOccEND = m_occupied.rend(); itOcc != itOccEND and not *itOcc; ++itOcc) {
+			++deleCount;
+		}
+
+		if (deleCount) {
+			assert(deleCount <= m_occupied.size());
+			const std::size_t newSize = m_occupied.size() - deleCount;
 			m_occupied.resize(newSize);
 			m_list.resize(newSize);
 		}