题解 | 自守数

import sys
while True:
    try:
        n = int(input())
        total = 1
        for i in range(1,n+1,10):
            l_i = len(str(i))
            if str(i*i)[-l_i:] == str(i):
                total += 1
        for i in range(5,n+1,10):
            l_i = len(str(i))
            if str(i*i)[-l_i:] == str(i):
                total += 1
        for i in range(6,n+1,10):
            l_i = len(str(i))
            if str(i*i)[-l_i:] == str(i):
                total += 1
        print(total)
    except:
        break