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: Runtime Error)

import java.util.*;
public class Main {
public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int N,K;
    N= sc.nextInt();
    K = sc.nextInt();
    ArrayList<Integer> list = new ArrayList<Integer>();
    ArrayList<Integer> list2 = new ArrayList<Integer>();
    for(int a=0;a<N;a++){
        int ai = sc.nextInt();
        int bi = sc.nextInt();
       list.add(ai);
       list2.add(bi);
    }
    int min_num=0;
    for(int a=K;a>0;a--){
        min_num =Collections.min(list);
        int nth=0;
        for(int b=0;b<list.size();b++){
            if(min_num == list.get(b)){
                nth =b;
                list.set(b,1000000000);
                a=a-list2.get(b);
                break;

            }
        }

    }
    System.out.println(min_num);
}
}