Полуфинал Республиканской олимпиады Азербайджана 2018-2019

Big array of Dino

Time limit 1 second
Memory limit 128 MiB

Once, when Dino was solving a problem related to arrays, he saw that the size of all arrays is at most 10^6. Since Dino is a dinosaur, this number seemed very small to him. Therefore, he decided to create a big array.

Dino first creates an empty array and selects n pairs of numbers: (a[1], b[1]), (a[2], b[2]), ..., (a[n], b[n]). Then for each of these pairs he inserts into array the number b[i] a[i] times. For example,if the first pair is (3, 5), the number 5 will be inserted into array 3 times. After that, Dino decides to arrange this array in non-decreasing order, but since the array is very large, Dino's computer cannot perform this arrangement. He is interested in the k-th (the array is numbered starting from 1) number. Help Dino to find this number.

Input data

First line contains number n (1n10^5). Each of the next n lines contains pair (a[i], b[i]) (1a[i], b[i]10^5). The last line contains number k. It is guaranteed that k-th number exists in array.

Output data

Print the k-th number in non-decreasing array.


Input example #1
1 2
3 6
2 1
Output example #1
Source 2019-2020 Republic Azerbaijan, Semifinals