while True: try: n = int(input()) res = [] for i in range(0,n + 1): if str(i**2)[-len(str(i)):] == str(i):#或者用endswith方法,if str(i**2).endswith(str(i)): res.append(i) print(len(res)) except: break
while True: try: n = int(input()) res = [] for i in range(0,n + 1): if str(i**2)[-len(str(i)):] == str(i):#或者用endswith方法,if str(i**2).endswith(str(i)): res.append(i) print(len(res)) except: break