image.png
import java.util.Scanner;
public class Main {
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int[] a = new int[n];
for(int i = 0; i < n; i++){
a[i] = sc.nextInt();
}
int b = sc.nextInt();
for(int i = 0; i < n; i++){
if(b==a[i]){
System.out.println(i+1);
return;
}
}
System.out.println(-1);
}
}
