N, K = map(int, input().split())
A = list(map(int, input().split()))
dp = [[0] * (K + 1) for i in range(N + 1)]
dp2 = [[0] * (K + 1) for i in range(N + 1)]
dp[0][0] = 1
dp2[0][0] = 1
for i in range(N):
    for j in range(K + 1):
        dp[i + 1][j] |= dp[i][j]
        dp2[i + 1][j] |= dp2[i][j]
        if j - A[i] >= 0:
            dp[i + 1][j] |= dp[i][j - A[i]]
        if j - A[N - 1 - i] >= 0:
            dp2[i + 1][j] |= dp2[i][j - A[N - 1 - i]]

if not dp[N][K]:
    print(-1)
    exit()

ans = 0
for i in range(1, N):
    flag = 0
    for k in range(K + 1):
        flag |= (dp[i][K - k] & dp2[N - i - 1][k])
    if flag:
        ans += 1
print(ans)