#include <cstdio>
#include <algorithm>


using namespace std;



int main() {
    int n;
    scanf("%d", &n);
    int x[100];
    for (int i = 0; i < n; ++i)
        scanf("%d", x + i);
    sort(x, x + n);
    int a;
    scanf("%d", &a);

    int idx = -1;
    int begin = 0;
    int end = n - 1;
    while (begin <= end) {
        int mid = (begin + end) >> 1;
        if (x[mid] >= a)
            end = mid - 1;
        else {
            idx = mid;
            begin = mid + 1;
        }
    }
    if (idx == -1)
        printf("-1\n");
    else
        printf("%d\n", x[idx]);
    return 0;
}