import sys

int1 = lambda x: int(x) - 1

# input = lambda: sys.stdin.buffer.readline()
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
i1 = lambda: int1(input())
mi = lambda: map(int, input().split())
mi1 = lambda: map(int1, input().split())
li = lambda: list(mi())
li1 = lambda: list(mi1())
lli = lambda n: [li() for _ in range(n)]

INF = float("inf")
mod = int(1e9 + 7)
# mod = 998244353

n, k = mi()
a = li()
dp = [[0] * (n + 1) for i in range(k + 1)]
dp[0][0] = 1
for i in range(n):
    for j in range(k + 1):
        if dp[j][i]:
            if j + a[i] <= k:
                dp[j + a[i]][i + 1] = 1
            dp[j][i + 1] = 1
if not dp[k][n]:
    print(-1)
    exit(0)
dp[k][n] = 2
ans = 0
for i in range(n, 0, -1):
    c = 1
    for j in range(k + 1):
        if dp[j][i] == 2:
            if dp[j][i - 1]:
                dp[j][i - 1] = 2
                c = 0
            if j - a[i - 1] >= 0 and dp[j - a[i - 1]][i - 1]:
                dp[j - a[i - 1]][i - 1] = 2
    ans += c
print(ans)