Problem:
Score : 300 points

Problem 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.

Constraints

1≤N≤10^5

1≤a_i,b_i≤10^5

1≤K≤b_1…+…b_n

All input values are integers.

Input

Input is given from Standard Input in the following format:

N K
a_1 b_1
:
a_N b_N

Output

Print the K-th smallest integer in the array after the N operations.

Sample Input 1

3 4
1 1
2 2
3 3

Sample Output 1

3

The resulting array is the same as the one in the problem statement.

Sample Input 2

10 500000
1 100000
1 100000
1 100000
1 100000
1 100000
100000 100000
100000 100000
100000 100000
100000 100000
100000 100000

Sample Output 2

1

Solution in Julia (0.5.0) (judge verdict: Wrong Answer)

function main()
  
  (N,K) = map(x -> parse(Int,x), split(readline()))
  
  (n,b) = map(x -> parse(Int,x), split(readline()))
  
  a = [n for i in 1:b]
  
  for i in 1:N-1
    
    (n,m) = map(x -> parse(Int,x), split(readline()))
    
    for j in 1:m
      push!(a,n)
    end
    
  end
  
  sort!(a)
  
  println(a[4])
  
end

main()