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 data[200000];
int mou[200000];
int main(void){
    int n,tgt,i,j,min,minmo,minj,td,tm,x;
    scanf("%d %d",&n,&tgt);
    for(i=0;i<n;i++)scanf("%d %d",&data[i],&mou[i]);
    x=0;
    while(1){
        min=200000;
        for(i=0;i<n;i++){
            if(mou[i]>0&&data[i]<min){
                minj=i;
                min=data[i];
            }
        }
        x+=mou[minj];
        mou[minj]=-1;
        if(x>=tgt)break;
    }
    printf("%d\n",data[minj]);
    return 0;
}