import collections

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

CA = collections.Counter(A)
if sum(A)==K:
    print(N)
    exit()
if CA[1]>K:
    print(0)
    exit()


A.sort()
DP = [-1]*(K+1)
for i in range(N):
    for j in reversed(range(K)):
        if DP[j]!=-1 and j+A[i]<=K and DP[j+A[i]]==-1:
            DP[j+A[i]]=i
        else:
            pass
    if DP[K]!=-1:
        break
    if DP[A[i]]==-1:
        DP[A[i]]=i
if DP[K]==-1:
    print(-1)
    exit()
v = K
B = []
while v>0:
    B.append(A[DP[v]])
    v-=A[DP[v]]
ans = 0
minb = min(B)
CB = collections.Counter(B)

A.sort(reverse=True)
DP = [-1]*(K+1)
for i in range(N):
    for j in reversed(range(K)):
        if DP[j]!=-1 and j+A[i]<=K and DP[j+A[i]]==-1:
            DP[j+A[i]]=i
        else:
            pass
    if DP[K]!=-1:
        break
    if DP[A[i]]==-1:
        DP[A[i]]=i
if DP[K]==-1:
    print(-1)
    exit()
v = K
B = []
while v>0:
    B.append(A[DP[v]])
    v-=A[DP[v]]
ans = 0
minb = min(B)
CC = collections.Counter(B)

CC = CC-CB

for k,v in CB.items():
    if CB[k]==CA[k]:
        DP = [-1]*(K+1)
        for i in range(N):
            if A[i]==k:
                continue
            for j in reversed(range(K)):
                if DP[j]!=-1 and j+A[i]<=K and DP[j+A[i]]==-1:
                    DP[j+A[i]]=i
                else:
                    pass
            if DP[K]!=-1:
                break
            if DP[A[i]]==-1:
                DP[A[i]]=i
        if DP[K]==-1:
            ans+=v


for k,v in CC.items():
    if CC[k]==CA[k]:
        DP = [-1]*(K+1)
        for i in range(N):
            if A[i]==k:
                continue
            for j in reversed(range(K)):
                if DP[j]!=-1 and j+A[i]<=K and DP[j+A[i]]==-1:
                    DP[j+A[i]]=i
                else:
                    pass
            if DP[K]!=-1:
                break
            if DP[A[i]]==-1:
                DP[A[i]]=i
        if DP[K]==-1:
            ans+=v

print(ans)