diff --git a/arithmetic.cpp b/arithmetic.cpp
index d6bcd30..e453712 100644
--- a/arithmetic.cpp
+++ b/arithmetic.cpp
@@ -2,6 +2,6 @@
 #include "arithmetic.h"
 int add(int a, int b)
 {
-int c = a + b;
-return c;
+	int c = a + b;
+	return c;
 }
diff --git a/main.cpp b/main.cpp
index af6710b..74601a4 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,8 +1,10 @@
 #include <iostream>
 #include "arithmetic.h"
+#include "opencv2/opencv.hpp"
 int main()
 {
-std::cout << "Hello world!" << std::endl;
-std::cout << "c= " << add(1,2) << std::endl;
-return 0;
+	std::cout << "Hello world!" << std::endl;
+	std::cout << "c= " << add(1,2) << std::endl;
+	return 0;
+	
 }
diff --git a/makefile b/makefile
index 052cd56..9a8464a 100644
--- a/makefile
+++ b/makefile
@@ -1,7 +1,7 @@
 all: main arithmetic
-	g++ arithmetic.o main.o
+	g++ arithmetic.o main.o -L/usr/lib/x86_64-linux-gnu -lopencv_core
 main: main.cpp
-	g++ -c main.cpp
+	g++ -c main.cpp -I/usr/include/opencv4
 arithmetic: arithmetic.cpp arithmetic.h
 	g++ -c arithmetic.cpp
 clean: