#include <iostream>
using namespace std;
int main() {
    int m;
    cin>>m;
    int a[m];
    for(int i=0;i<m;i++){
    	cin>>a[i];
    	
    }
    int n;
    cin>>n;
    int p=-1;
    for(int i=0;i<m;i++){
    	if(a[i==n]) {
    	p=i+1;
    	break;
    	}
    }
    cout<<p;
}
/**************************************************************
	Problem: 1154
	User: fandaohan
	Language: C++
	Result: Wrong Answer
****************************************************************/