#include<iostream>
using namespace std;
int main()
{
    int n;
    cin>>n;
    int arr[n];
    for(int i=0;i<n;i++)
    {
        cin>>arr[i];
    }
    int target;
    cin>>target;
    int count =0;
    for(int i=0;i<n;i++)
    {
        if(arr[i]==target)
        
        {
           count++;
           if(count==2)
           {
               icout<<i;
               return 0;
           }
        }
    }
    cout<<" key is not found ";
}