题解 | #自守数#

from math import sqrt
import sys

for line in sys.stdin:
    a = int(line.strip())
    count = 0 
    for i in range(0,a+1):
        sqrt =  i**2 # 平方
        if i in (0,1,5) and i<=5:
            count += 1
        elif i>5:
            # print(sqrt,'====')
            # print(str(sqrt))

            center = -len(str(sqrt)) / 2
            # print(center,'=========')

            last = str(sqrt)[-int(center):] 
            if last == str(i):
                count += 1

    print(count)