title: invalid literal for int() with base 10: '' error
body: <p>I just started coding about 5 weeks ago and I am working on a code for my game development class and I'm just terribly stuck on an issue. When I run my code, I get the "ValueError: invalid literal for int() with base 10: ''" error and I'm unsure of what I'm doing wrong. I'll post my code below. Any help is appreciated. Thank you!</p>
  
  <pre><code>start = 0
  def addition(num1):
      return num1 + num1
  
  def square(num):
      print("I'm in square")
      return num * num
  
  def display(message):
      """Display game instuctions"""
      print(message)
  def instructions():
      """Display game instuctions"""
      print("Welcome to the world's greatest game")
  
  
  def main():
      instructions()
      scores = [("Roger", 3456), ("Justin", 2320), ("Beth", 1422)]
  
      start = input("Would you like to view the high score options? y/n ")
      if start == "y":
          print("""\
          Hello! Welcome to the high scores!
          Here are the current high score leaders!:
          """)
          print(scores)
          print("""\n\
          0 - Sort high scores
          1 - Add high score
          2 - Reverse the order
          3 - Remove a score
          4 - Square a number
          5 - Add 2 numbers together
          """)
          option = int(input())
          while option &lt; 6:
              start = int(input("Please enter your selection")) 
              print(scores)
              if option == 0:
                  scores.sort()
                  print("These are the scores sorted alphabetically")
                  print(scores)
              if option == 1:
                  print(scores)
                  print("Please enter your name and score; After entering your name, hit the return key and enter your score")
                  name = input()
                  score = int(input())
                  entry = (name,score)
                  scores.append(entry)
                  print(scores)
              if option == 2:
                  print(scores)
                  scores.reverse()
                  print("\nHere are the scores reversed")
                  print(scores)
              if option == 3:
                  print(scores)
                  print("Please enter the high score you would like to remove. After typing the name, hit the return key and enter the score")
                  name1 = input()
                  score1 = int(input())
                  remove = (name1,score1)
                  scores.remove(remove)
                  print(scores)
              if option == 4:
                  val = int(input("Give me a number to square"))
                  sqd = square(val)
                  print(sqd)
              if option == 5:
                  val0 = int(input("Give me one number"))
                  val1 = int(input("Give me another number"))
                  addi = (val0 + val1)
                  print(addi)
  
  main()
  </code></pre>