#include<iostream>
#include<cstdio>
using namespace std;
int maxn=200+10;
int main(){
    int arr[maxn];
    int n;
    while(scanf("%d",&n)!=EOF){
        for(int i=0;i<n;i++){
            scanf("%d",&arr[i]);
        }
        int x;
        int answer=-1;
        scanf("%d",&x);
        for(int i=0;i<n;i++){
            if(arr[i]==x){
                answer=i;
                break;
            }
            }
            printf("%d\n",answer);
        }
    return 0;
}