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.lang.*;
import java.util.*;
import java.io.*;

public class Main {
    public static void main(String args[]) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));  
        
        String[] nk = br.readLine().split(" ");
        int n = Integer.parseInt(nk[0]);
        int k = Integer.parseInt(nk[1]);
        long[] arr = new long[100001];
        
        for(int i = 0; i < n; i++){
            String[] vq = br.readLine().split(" ");
            int v = Integer.parseInt(vq[0]);
            int q = Integer.parseInt(vq[1]);
            arr[v] += q;
        }
        
        long sum = 0;
        
        for(int i = 1; i < 100001; i++){
            sum += arr[i];
            if(sum >= k){
                System.out.println(i);
                break;
            }
        }

    }
}