n = int(input())
a = [int(x) for x in input().split()]
s = int(input())
if sum(a) <= s:
    print(0)
else:
    min_len = 10**9
    for i in range(n):
        for j in range(i, n):
            tong_xoa = sum(a[i:j+1])
            tong_con_lai = sum(a) - tong_xoa

            if tong_con_lai <= s:
                do_dai_xoa = j - i + 1
                if do_dai_xoa < min_len:
                    min_len = do_dai_xoa
    if min_len == 10**9:
        print(-1)
    else:
        print(min_len)