#include<stdio.h>
#include<stdlib.h>
typedef struct list
{
    int data;
    struct list *next;
}node;
node *head=NULL,*tail=NULL;

void create(int n)
{
    node *newnode=(node*)malloc(sizeof(node));
    newnode->data=n;
    newnode->next=NULL;
    if(head==NULL)
    {
        head=tail=newnode;
    }
    else
    {
        tail->next=newnode;
        tail=newnode;
    }
}
void traverse(int n,int itr)
{
    int count=0;
    node*temp=head;
    while(tenp!=NULL)
    {
        count+=1;
        if(temp->data==n)
        {
            
            break;
        }
        temp=temp->next;
    }
    if(count==itr)
    {
        printf("-1");
    }
    else
    {
        printf("%d",count);
    }
}
void main()
{
    int n,data,search;
    scanf("%d",&n);
    for(int i=0;i<n;i++)
    {
        scanf("%d",&data);
        create(data);
    }
    scanf("%d",&search);
    traverse(search,n);
}