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)

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

MwoxIDIgMAo1

3
1 2 0
5