diff --git a/Parameters.hpp b/Parameters.hpp
index 65bd563..de45b24 100644
--- a/Parameters.hpp
+++ b/Parameters.hpp
@@ -22,7 +22,7 @@ public:
 			std::string arg = argv[i];
 			if (0 == arg.compare(0, 2, "-w"))
 			{
-				workerCount_ = std::stoi(arg.substr(2));
+				workerCount_ = std::stoul(arg.substr(2));
 			}
 			else if (0 == arg.compare(0, 1, "-"))
 			{