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: Runtime Error)

#include<stdio.h>
int main()
{
	int N, K, h;
	scanf("%d %d", &N, &K);
	int a[N];
	int b[N];
	int ro;
	int op;
	int sum = 0;
	int doko=0;
	
	for(ro=0; ro<N; ro++)
	{
		scanf("%d %d", &a[ro], &b[ro]);
		sum = sum+ b[ro];
	}
  
 
   for(ro=0; ro<N; ro++){
		for(op=0; op<N-1; op++){
			if(b[op+1] < b[op]){
				h = b[op];
				b[op] = b[op+1];
				b[op+1] = h;
            }
			}
		}
	
	int C[sum];
   
  for(ro=0; ro<N; ro++)
  {
    for(op=0; op<b[ro]; op++)
    {
      C[doko+op] = a[ro];
    }
    doko = doko+ b[ro];
  }
 
  
  
  printf("%d", C[K-1]);
  
return 0;
}