Problem:
Score : 200 points

Problem Statement

Today is August 24, one of the five Product Days in a year.

A date m-d (m is the month, d is the date) is called a Product Day when d is a two-digit number, and all of the following conditions are satisfied (here d_{10} is the tens digit of the day and d_1 is the ones digit of the day):

d_1 \geq 2

d_{10} \geq 2

d_1 \times d_{10} = m

Takahashi wants more Product Days, and he made a new calendar called Takahashi Calendar where a year consists of M month from Month 1 to Month M, and each month consists of D days from Day 1 to Day D.

In Takahashi Calendar, how many Product Days does a year have?

Constraints

All values in input are integers.

1 \leq M \leq 100

1 \leq D \leq 99

Input

Input is given from Standard Input in the following format:

M D

Output

Print the number of Product Days in a year in Takahashi Calender.

Sample Input 1

15 40

Sample Output 1

10

There are 10 Product Days in a year, as follows (m-d denotes Month m, Day d):

4-22

6-23

6-32

8-24

9-33

10-25

12-26

12-34

14-27

15-35

Sample Input 2

12 31

Sample Output 2

5

Sample Input 3

1 1

Sample Output 3

0

Solution in C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;

namespace JSC2019A
{
    class Program
    {
        static void Main(string[] args)
        {
            var input = Console.ReadLine().Split().Select(x => int.Parse(x)).ToArray();
            var M = input[0];
            var D = input[1];

            var primes = new HashSet<int> { 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97 };
            var ans = 0;

            foreach (var m in Enumerable.Range(1, M).Where(x => x > 3 && !primes.Contains(x)))
            {
                for (var i = 2; i < m; i++)
                {
                    if (m % i != 0)
                        continue;

                    var rem = 0;
                    var div = Math.DivRem(m, i, out rem);
                    if (rem != 0 || (i.ToString() + div.ToString()).Length > 2 || i * 10 + div > D)
                        break;

                    ans += 1;
                    Console.WriteLine($"{m:00}月{i}{div}日");
                }
            }
            Console.WriteLine(ans);
        }
    }
}