n = input() count = 0 for i in range(eval(n)+1): lenth = len(str(i)) num = i**2 if str(num)[-lenth:] == str(i): count += 1 print(count)
n = input() count = 0 for i in range(eval(n)+1): lenth = len(str(i)) num = i**2 if str(num)[-lenth:] == str(i): count += 1 print(count)