output_description: Print the number of people sitting at the theater.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      l_1 r_1
      :
      l_N r_N
attempt: import math
  import sys
  
  
  def getinputdata():
  
      # 配列初期化
      array_result = []
  
      data = input()
  
      array_result.append(data.split(" "))
  
      flg = 1
  
      try:
  
          while flg:
  
              data = input()
  
              array_temp = []
  
              if data != "":
  
                  array_result.append(data.split(" "))
  
                  flg = 1
  
              else:
  
                  flg = 0
      finally:
  
          return array_result
  
  
  arr_data = getinputdata()
  
  n = int(arr_data[0][0])
  
  mysum = 0
  
  for v in range(1, 1 + n):
  
      mysum += int(arr_data[v][1]) - int(arr_data[v][0]) + 1
  # print("Yes"   if "9"  in n else "No")
  
  print(mysum)
  
problem_description: Statement
  
  Joisino is working as a receptionist at a theater.
  
  The theater has 100000 seats, numbered from 1 to 100000.
  
  According to her memo, N groups of audiences have come so far, and the i-th
  group occupies the consecutive seats from Seat l_i to Seat r_i (inclusive).
  
  How many people are sitting at the theater now?
samples: [{"input": "1\n    24 30", "output": "7\n    \n\nThere are 7 people, sitting at Seat 24,25,26,27,28,29 and 30.\n\n* * *"}, {"input": "2\n    6 8\n    3 3", "output": "4"}]