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.*;


/**
 * Created by Seiya on 2016/10/16.
 */

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        long[] map = new long[100002];

        int n = scanner.nextInt();
        int k = scanner.nextInt();

        for (int i = 0; i < n; i++) {
            int a = scanner.nextInt();
            int b = scanner.nextInt();
            map[a] += b;
        }

        long total = 1;
        for (int i = 0; i < 100001; i++) {
            total += map[i];
            if(total > k){
                System.out.println(i);
                break;
            }
        }


    } // mainMethod


} // MainClass