import sys,random,bisect
from collections import deque,defaultdict
from heapq import heapify,heappop,heappush
from itertools import permutations
from math import log,gcd

input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

N,K = mi()
A = li()

assert N <= 10**4
assert K <= 10**3

dp = [0 for i in range(N+1)]
dp[0] = 1
for i in range(N):
    dp[i+1] = dp[i]|(dp[i]<<A[i])

dp_back = [0 for i in range(N+1)]
dp_back[N] = 1
for i in range(N)[::-1]:
    dp_back[i] = dp_back[i+1]|(dp_back[i+1]<<A[i])

if dp[-1]>>K & 1 == 0:
    exit(print(-1))

need = 0
for i in range(N):
    flag = True
    for k in range(K+1):
        if dp[i]>>k & 1:
            if dp_back[i+1]>>(K-k) & 1:
                flag = False
    if flag:
        need += 1


print(need)