N, K = map(int, input().split())
A = list(map(int, input().split()))

MASK = (1 << (K + 1)) - 1

dpl = [0 for _ in range(N + 1)]
dpr = [0 for _ in range(N + 1)]
dpl[0] = 1
dpr[N] = (1 << K)

for i in range(N):
    dpl[i + 1] = (dpl[i] | (dpl[i] << A[i])) & MASK
for i in range(N - 1, -1, -1):
    dpr[i] = (dpr[i + 1] | (dpr[i + 1] >> A[i])) & MASK
if (dpl[N] & (1 << K)) == 0:
    print(-1)
else:
    ans = N
    for i in range(N):
        if dpl[i] & dpr[i + 1]:
            ans -= 1
    print(ans)