#include<bits/stdc++.h> using namespace std; int main(){ int a,b[10000],c,t; cin>>a; for (int i=1;i<=a;i++)cin>>b[i]; cin>>c; for(int d=1;d<=a;d++) {if(b[d]==c) {cout<<d-1; goto q; } else t++;} if(t==a)cout<<-1; q:cout<<endl; return 0; }
