N,S = list(map(int,input().split()))
S *= 10**6
A = list(map(lambda x:int(x)*10**6,input().split()))
A.sort()

def check(n):
    v = S - len([i for i in A if i <= n * 10**6])
    B = [i for i in A if i > n * 10**6]
    for i in B:v -= i+1
    return v >= 0

check(1)

ng,ok = 0,10**18
while(ok - ng > 1):
    mid = (ok+ng)//2
    if(check(mid)):
        ok = mid
    else:
        ng = mid
print(ok)