import sys
N, M = map(int, sys.stdin.readline().split())
num = list(map(int, sys.stdin.readline().split()))
num.sort()
left = 0
right = max(num)
answer = 0
while left <= right:
cnt = (left + right) // 2
cut = 0
for i in num:
if i >= cnt:
cut += i - cnt
# if cut == M:
# print(cnt)
# break
if cut < M:
right = cnt -1
else:
answer = cnt
left = cnt + 1
print(answer)