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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
class Pare {
    int a;
    int b;
    public Pare(int a, int b) {
	this.a = a;
	this.b = b;
    }
    public int getA(){
	return a;
    }
}

class Main {
    public static void main(String[] args) {
	Scanner sc = new Scanner(System.in);
	int N = Integer.parseInt(sc.next());
	long K = Long.parseLong(sc.next());
	Pare[] p = new Pare[N];

	for(int i = 0; i<N; i++) {
	    p[i] = new Pare(Integer.parseInt(sc.next()),Integer.parseInt(sc.next()));
	}
	Arrays.sort(p,Comparator.comparing(Pare::getA));

	long cnt = 0;
	for(int i = 0; i<N; i++) {
	    cnt += p[i].b;
	    if(cnt >= K) {
		System.out.println(p[i].a);
		return;
	    }
	}


    }
}