#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;
}