C++ :

#include<bits/stdc++.h>
using namespace std;


int main() {
	int n,a[110],m,x,p = -1;
	cin>>n;
	int i;
	for(i = 0; i < n; i++) {
		cin>>a[i];
	}
	cin>>x;
	for(i = 0; i < n; i++) {
		if(a[i] == x){
			p = i + 1;
		}
	}
	
	cout<<p;
}

Java :

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 m = sc.nextInt();
	int p = 0;
	boolean f = false;
	for(int i = 0; i < n ; i++) {
		
		if(m == a[i]) {
			p = i + 1;
			f = true;
		}
	}
	if(f == false) {
		System.out.print(-1);	
	}else {
		System.out.print(p);
	}
	
	
	

}
}

Python :

n = int(input())
s = input().split()
k = int(input())
f = -1
for i in range(len(s) - 1, -1, -1):
    if int(s[i]) == k:
        f = i + 1
        break
print(f)