output_description: Print the K-th smallest integer in the array after the N operations.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N K
      a_1 b_1
      :  
      a_N b_N
attempt: [
      [
          print(
              ab[
                  [
                      index
                      for index in [
                          SumI if NK[1] <= sum([ab[1][I] for I in range(SumI)]) else -1
                          for SumI in range(NK[0])
                      ]
                      if index != -1
                  ][0]
              ][0]
          )
          for ab in [
              sorted(
                  [list(map(int, (input().split()))) for i in range(NK[0])],
                  key=lambda x: x[0],
              )
          ]
      ]
      for NK in [list(map(int, (input().split())))]
  ]
  
problem_description: Statement
  
  There is an empty array. The following N operations will be performed to
  insert integers into the array. In the i-th operation (1≤i≤N), b_i copies of
  an integer a_i are inserted into the array. Find the K-th smallest integer in
  the array after the N operations. For example, the 4-th smallest integer in
  the array \\{1,2,2,3,3,3\\} is 3.
samples: [{"input": "3 4\n    1 1\n    2 2\n    3 3", "output": "3\n    \n\nThe resulting array is the same as the one in the problem statement.\n\n* * *"}, {"input": "10 500000\n    1 100000\n    1 100000\n    1 100000\n    1 100000\n    1 100000\n    100000 100000\n    100000 100000\n    100000 100000\n    100000 100000\n    100000 100000", "output": "1"}]