This is an interactive problem. You are given a sorted in increasing order singly linked list. You should find the minimum integer in the list which is greater than or equal to x . More formally, there is a singly liked list built on an array of n elements. Element with index i contains two integers: value i is the integer value in this element, and next i that is the index of the next element of the singly linked list (or -1 , if the current element is the last). The list is sorted, i.e. if next i ≠ - 1 , then value next i > value i . You are given the number of elements in the list n , the index of the first element start , and the integer x . You can make up to 2000 queries of the following two types: ? i ( 1 ≤ i ≤ n ) — ask the values value i and next i , ! ans — give the answer for the problem: the minimum integer, greater than or equal to x , or ! -1 , if there are no such integers. Your program should terminate after this query. Write a program that solves this problem. The first line contains three integers n , start , x ( 1 ≤ n ≤ 50000 , 1 ≤ start ≤ n , 0 ≤ x ≤ 10 9 ) — the number of elements in the list, the index of the first element and the integer x . To print the answer for the problem, print ! ans , where ans is the minimum integer in the list greater than or equal to x , or -1 , if there is no such integer. To make a query of the first type, print ? i ( 1 ≤ i ≤ n ), where i is the index of element you want to know information about. After each query of type ? read two integers value i and next i ( 0 ≤ value i ≤ 10 9 , - 1 ≤ next i ≤ n , next i ≠ 0 ). It is guaranteed that if next i ≠ - 1 , then value next i > value i , and that the array values give a valid singly linked list with start being the first element. Note that you can't ask more than 1999 queries of the type ? . If next i = - 1 and value i = - 1 , then it means that you asked more queries than allowed, or asked an invalid query. Your program should immediately terminate (for exam