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Полуфинал Республиканской олимпиады Азербайджана 2018-2019

Big array of Dino

Once, when Dino was solving a problem related to arrays, he saw that the size of all arrays is at most 106. 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: (a1, b1), (a2, b2), ..., (an, bn). Then for each of these pairs he inserts into array the number bi ai 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

First line contains number n (1n105). Each of the next n lines contains pair (ai, bi) (1ai, bi105). The last line contains number k. It is guaranteed that k-th number exists in array.

Output

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

Time limit 1 second
Memory limit 128 MiB
Input example #1
3
1 2
3 6
2 1
3
Output example #1
2
Source Semifinals, Azerbaijan Olympiad 2018-2019