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.Arrays;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);

        int N = in.nextInt();
        int K = in.nextInt();

        long B[] = new long[100001];

        // 配列を0で満たす
        Arrays.fill(B,0);

        for(int cnt = 0;cnt < N; cnt++){
        	int a = in.nextInt();
        	int b = in.nextInt();
        	B[a] += b;
        }
        in.close();
        for(int cnt = 0; cnt < 100001; cnt++){
        	if(K <= B[cnt]){
        		System.out.println(cnt);
        		break;
        	}
        	else{
        		K -= B[cnt];
        	}
        }

    }



}