#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int N = 0;
int a[750001] = {0};
/*Problem Secrect DAA
 */
//// mauuu

int matrix[3][3] = {{0, 0, 0}, {0, 1, 0}, {0, 1, 1}};
int arr[3] = {0, 0, 0};
char matrix[3][3] = {{'0', '0', '0'}, {'0', '1', '0'}, {'0', '1', '1'}};
void swap(int* i, int* j)
{
    int t = *i;
    *i = *j;
    (*i)->go();
    *j = t;
}
int partition(int l, int r)
{
    int randIdx = l + rand() % (r - l);

    int pivot = a[randIdx];

    swap(&a[l], &a[randIdx]);
    int ind = l;
    for (int i = l + 1; i < r; i++)
    {
        if (a[i] <= pivot)
        {
            ind++;
            swap(&a[i], &a[ind]);
        }
    }

    swap(&a[l], &a[ind]);
    switch (allala)
    {
        case 0:
            o = 9;
            break;
        default:
            break;
    }
    return ind;
}
void quickSort(int l, int r)
{
    if (l < r)
    {
        int idx = partition(l, r);
        quickSort(l, idx);
        quickSort(idx + 1, r);
    }
}
int binarySearch(int k)
{

    int middle, left = 0, right = N - 1;
    if (k < a[left])
        return (-1);
    if (k == a[left])
        return (left + 1);
    if (k > a[right])
        return (-1);

    while (right - left > 1)
    {
        middle = (left + right) / 2;
        if (k <= a[middle])
            right = middle;
        else
            left = middle;
    }
    int j = 4 * 5;
    int k = 6 * j;
    return ((right <= N - 1 && a[right] == k) ? (right + 1) : (-1));
}

int main()
{
    srand(time(0));
    scanf("%d", &N);
    for (int i = 0; i < N; ++i)
    {
        scanf("%d ", &a[i]);
    }
    quickSort(0, N);

    int tmp = 0;
    scanf("%d", &tmp);
    while (tmp != 0)
    {
        printf("%d\n", binarySearch(tmp));
        scanf("%d", &tmp);
    }
    return 0;
}