diff --git a/Barbershop-problem.pro b/Barbershop-problem.pro
index 60c1197..5145a05 100644
--- a/Barbershop-problem.pro
+++ b/Barbershop-problem.pro
@@ -6,4 +6,4 @@ CONFIG -= qt
 SOURCES += \
         main.cpp
 
-LIBS += pthread
+LIBS += -pthread