from heapq import heapify, heappop, heappush

N, M, *C = map(int, open(0).read().split())

heapify(C)
for _ in range(M):
    if len(C) == 0:
        print(N)
        break
    t = heappop(C)
    t -= 1
    if t != 0:
        heappush(C, t)
else:
    print(N - len(C))