diff --git a/Makefile b/Makefile
index 323563f..e7fab1f 100644
--- a/Makefile
+++ b/Makefile
@@ -1,10 +1,11 @@
+MAKEFILE
 # Define the compiler and compiler flags
 CXX := g++
 CXXFLAGS := -std=c++17 -Wall -g
 
 # Define the names for the executable, source files, and object files
 TARGET := main
-SOURCES := person.cpp utils.cpp main.cpp
+SOURCES := person.cpp utils.cpp main.cpp stacks/expressions_calculator.cpp
 OBJECTS := $(SOURCES:.cpp=.o)
 
 # Default rule to build the executable
@@ -15,17 +16,17 @@ $(TARGET): $(OBJECTS)
 	$(CXX) $(CXXFLAGS) -o $@ $(OBJECTS)
 
 # Generic rule to compile .cpp files into .o files
-# $@ is the target, $< is the first prerequisite
 %.o: %.cpp
 	$(CXX) $(CXXFLAGS) -c $< -o $@
 
 # Rules for explicit header dependencies
-# These rules tell make which object files depend on which header files.
-main.o: main.cpp person.h utils.h
+main.o: main.cpp person.h utils.h stacks/expressions_calculator.h
 person.o: person.cpp person.h
 utils.o: utils.cpp utils.h
+stacks/expressions_calculator.o: stacks/expressions_calculator.cpp stacks/expressions_calculator.h
 
 # Rule to clean up generated files
-.PHONY: clean
+.PHONY: cleanls
+
 clean:
 	rm -f $(OBJECTS) $(TARGET)