import sys
input = sys.stdin.readline

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

DP=[0]*N
MAX=(1<<(K+1))-1


now=1<<0

for i in range(N):
    a=A[i]
    now=(now|(now<<a))&MAX
    DP[i]=now

now=1<<0
DP2=[0]*N

for i in range(N-1,-1,-1):
    a=A[i]
    now=(now|(now<<a))&MAX
    DP2[i]=now

if (DP[-1] & (1<<K)) == 0:
    print(-1)
    exit()

ANS=0
for i in range(N):
    if i-1>=0:
        left=DP[i-1]
    else:
        left=1<<0

    if i+1<N:
        right=DP2[i+1]
    else:
        right=1<<0

    for l in range(K+1):
        r=K-l

        if (left & (1<<l) != 0) and (right & (1<<r) != 0):
            ANS+=1
            break

    #print(ANS,left,right)

print(N-ANS)