output_description: Print the number of sand in the upper bulb after t second.
  
  * * *
input_description: The input is given from Standard Input in the following format:
  
      
      
      X t
attempt: def getInt():
      return int(input())
  
  
  def getIntList():
      return [int(x) for x in input().split()]
  
  
  def zeros(n):
      return [0] * n
  
  
  INF = 10**18
  
  
  class Debug:
      def __init__(self):
          self.debug = True
  
      def off(self):
          self.debug = False
  
      def dmp(self, x, cmt=""):
          if self.debug:
              if cmt != "":
                  w = cmt + ": " + str(x)
              else:
                  w = str(x)
              print(w)
          return x
  
  
  def prob():
      d = Debug()
      d.off()
      X, T = getIntList()
      return max(X - T, 0)
  
  
  ans = prob()
  print(ans)
  
problem_description: Statement
  
  We have a sandglass that runs for X seconds. The sand drops from the upper
  bulb at a rate of 1 gram per second. That is, the upper bulb initially
  contains X grams of sand.
  
  How many grams of sand will the upper bulb contains after t seconds?
samples: [{"input": "100 17", "output": "83\n    \n\n17 out of the initial 100 grams of sand will be consumed, resulting in 83\ngrams.\n\n* * *"}, {"input": "48 58", "output": "0\n    \n\nAll 48 grams of sand will be gone, resulting in 0 grams.\n\n* * *"}, {"input": "1000000000 1000000000", "output": "0"}]