diff --git a/hw01/main.py b/hw01/main.py
index f931dcc..020d1d7 100644
--- a/hw01/main.py
+++ b/hw01/main.py
@@ -1,11 +1,13 @@
 def add(x,y):
     return x+y
 
+def sub(x,y):
+    return x-y
 
 def calc():
     while(True):
-        operation = input("Enter operation from [+]: ")
-        if operation == "+":
+        operation = input("Enter operation from [+,-]: ")
+        if operation =="+" or operation == "-":
             break
         print("Enter valid operation")
 
@@ -15,6 +17,9 @@ def calc():
     if operation == "+":
         print(add(x,y))
 
+    if operation == "-":
+        print(sub(x,y))
+
 
 if __name__ == "__main__":
     calc()
\ No newline at end of file