completed minus func

calc.py

@@ -29,10 +29,14 @@ def summ():
             print("Error, enter correct number")
 def minus():
     print("Enter number(s) to minus, enter spase to calculate")
-    total = 0
+    try:
+        total = float(input("Enter First number \n"))
+    except ValueError:
+        print("Enter a valid number")
+        return
     while True:
-        num_input = input()
-        if num_input == " ":
+        num_input = input("Enter numbers to minus\n")
+        if num_input == " " or num_input == "":
             print(total)
             main()
         try: