#include <iostream>
#include <bits/stdc++.h>
using namespace std;


    int search(vector<int>& nums, int target) {
        int n = nums.size();
        int low = 0;
        int high = n - 1;
        while (low <= high) {
            int mid = low + (high - low) / 2;
            if (nums[mid] == target) {
                return mid;

            } else if (nums[mid] < nums[n - 1]) {
                if (target <= nums[n - 1]) {
                    if (nums[mid] > target) {
                        high = mid - 1;
                    } else {
                        low = mid + 1;
                    }
                } else {
                    high = mid - 1;
                }
            } else {
                if (target >= nums[0]) {
                    if (nums[mid] > target) {
                        high = mid - 1;
                    } else {
                        low = mid + 1;
                    }
                } else {
                    low = mid + 1;
                }
            }
        }

        return -1;
    }


int main() {
	// your code goes here
	
	int n;
	int target;
	cin>>n;
	cin>>target;
	
	vector<int> nums(n);
	
	
	for(int i=0;i<n;i++){
		cin>>nums[i];
		
	}
	
	cout<<search(nums,target);
	
	return 0;
}