n,k=map(int,input().split())
dp=[[0]*(k+1) for i in range(n+1)]
a=list(map(int,input().split()));dp[0][0]=1
for i in range(n):
    for j in range(k+1):
        dp[i+1][j]+=dp[i][j]
        if j+a[i]<=k:
            dp[i+1][j+a[i]]+=dp[i][j]
ans=0;c=dp[n][k]
if c==0:
	print(-1);exit()
for i in range(k+1):
    dp[n][i]=0
dp[n][k]=1
for i in range(n-1,-1,-1):
    s=1
    for j in range(k+1):
        if dp[i][j] and dp[i+1][j]:
            s=0
        if dp[i][j]:
            if j+a[i]<=k and dp[i+1][j+a[i]] or dp[i+1][j]:
                dp[i][j]=1
            else:
                dp[i][j]=0
    ans+=s
print(ans)