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: Wrong Answer)

import java.io.*;
import java.util.*;
import java.util.ArrayList;
public class Main{
	public static void main(String [] args){
    // InputStreamReader isr = new InputStreamReader(System.in);
    // BufferedReader br = new BufferedReader(isr);
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		long k = sc.nextLong();
		long sumel = 0;
		int flag = 0;
		long ans = 0;
		long a  = 0;
		long b  = 0;
		for(long i = 0; i < n;i++){
			a = sc.nextLong();
			b = sc.nextLong();
			sumel+=b;
			if(sumel>=k&&flag==0)
			{
				ans = a;
				flag = 1;
			}
		}
		if(flag!=0)
		System.out.println(ans);
}
}