Update Lesson 2 Task 3 to make it more simple

Lesson_2/task3.py

@@ -2,26 +2,21 @@
 # Author: Stanislav Mykhailenko
 # License: Unlicense
 
-# Return codes:
-# 0 - OK
-# 1 - Invalid number entered
-
-import math, sys
-
-def numberError():
-	print("Invalid number entered.")
-	sys.exit(1)
+error = False
 
 try: number = int(input("Enter a natural number: "))
-except ValueError: numberError()
+except ValueError: error = True
 
-if number < 1: numberError()
+if not error and number < 1: error = True
 
-while number > 0:
-	currentNumber = number
-	while currentNumber > 0:
-		print(currentNumber, end='')
-		if currentNumber > 1: print(' ', end='')
-		currentNumber = currentNumber - 1
-	print('')
-	number = number - 1
+if not error:
+	while number > 0:
+		currentNumber = number
+		while currentNumber > 0:
+			print(currentNumber, end='')
+			if currentNumber > 1: print(' ', end='')
+			currentNumber = currentNumber - 1
+		print('')
+		number = number - 1
+else:
+		print("Invalid number entered.")