N, M = list(map(int, input().split()))
C = list(map(int, input().split()))
zero_count = 0
C.sort()
for i in range(M+1):
    if C[0] == 0:
        zero_count += 1
        C.pop(0)
    if len(C) == 0:
        break
    C[0] -= 1

print(zero_count)