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 Python (3.4.3) (judge verdict: Time Limit Exceeded)

#nm = '3 4'.split(' ')
#print(abc)
nm = input().split(' ')
vv = []
ss =[]
vv.append(input().split(' '))

for i in range(int(nm[0])-1):
    a = input().split(' ')
    if int(a[0]) > int(vv[-1][0]):
        vv.append(a)
    else:
        vv.insert(0, a)

cou = 0
for i in vv:
    if  cou < int(nm[1]):    
        for f in range(int(i[0])):
            ss.append(int(i[1]))
    cou += int(i[0])



        
sub = len(ss)-1
while sub != 0:

    ss[sub], ss[ss.index(max(ss[:sub+1]))] = ss[ss.index(max(ss[:sub+1]))], ss[sub] 
    sub -= 1

print(ss[int(nm[1])])