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.util.Scanner;
import java.util.Arrays;

class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
		long K = sc.nextLong();

		int a;
		int b;

		int[] array = new int[100001];
		for(int i=1; i<=100000; i++){
			array[i] = 0;
		}

		for(int i=0; i<N; i++){
			a = sc.nextInt();
			b = sc.nextInt();
			array[a] += b;
		}

		int ans = 0;
		for(int i=1; i<=100000; i++){
			K -= array[i];
			if(K<=0){
				ans = i;
				break;
			}
		}

    System.out.print(ans);

	}

}