N,M = map(int,input().split())
C = list(map(int,input().split()))
C = sorted(C)
counter = 0
answer = 0
while counter < M+1 :
    if len(C) == 0 :
        break
    elif C[0] != 0 :
        C[0] -= 1
        counter += 1
        C = sorted(C)
    else :
        answer += 1
        C.pop(C[0])
print(answer)