def main():
    N, M = map(int, input().split())
    C = list(map(int, input().split()))
    C.sort()
    for _ in range(M):
        C[0] -= 1
        if C[0] == 0:
            C.pop(0)
    print(N-len(C))
    
        
    
    
if __name__ == '__main__':
    main()