#include<iostream>
using namespace std;
int func(int a[], int n, int cur, int key){
if(cur == n) return -1;
if(a[cur]==key)
return cur;
return func(a,n,cur+1,key);
}
int main() {
int n;
cin>>n;
int a[n];
for(int i=0;i<n;i++){
cin>>a[i];
}
int key;
cin>>key;
cout<<func(a,n,0,key);
return 0;
}
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