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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>


int main(void){
    int i, n, k, ab1[100000], ab2[100000], num = 0, num2 = 0;
    
    scanf("%d %d", &n, &k);
    
    for(i=0; i<n; i++){
        scanf(" %d %d", &ab1[i], &ab2[i]);
    }
   
    for(i=0; i<n; i++){
        num = num + ab2[i];
        if(num > k){
            
            num2 =  (num - k);
           // printf("num2->%d\n", num2);
           // printf("num->%d\n", num);
            if( ab2[i] - num2 >= 1 ) {
                printf("%d\n", ab1[i]);
                break;
            }else{
                printf("%d\n", ab1[i-1] );
                break;
            }
        }
    }
    
    
    return 0;
    
}