n,k = map(int,input().split())
A = list(map(int,input().split()))

dp = [[0]*(k+1) for i in range(n+1)]
dp[0][0] = 1
for i,a in enumerate(A):
    for j in range(k+1):
        if dp[i][j] == 0:
            continue

        dp[i+1][j] = 1
        if j+a <= k:
            dp[i+1][j+a] = 1

A = A[::-1]
dp2 = [[0]*(k+1) for i in range(n+1)]
dp2[0][0] = 1
for i,a in enumerate(A):
    for j in range(k+1):
        if dp2[i][j] == 0:
            continue

        dp2[i+1][j] = 1
        if j+a <= k:
            dp2[i+1][j+a] = 1

if dp[-1][k] == 0:
    print(-1)
    exit()


ans = 0
for i in range(n):
    find = 1
    for j in range(k+1):
        if dp[i][j] and dp2[n-i-1][k-j]:
            find = 0
    ans += find
print(ans)