Problem:
Score : 500 points

Problem Statement

Takahashi has a string S of length N consisting of digits from 0 through 9.

He loves the prime number P. He wants to know how many non-empty (contiguous) substrings of S - there are N \times (N + 1) / 2 of them - are divisible by P when regarded as integers written in base ten.

Here substrings starting with a 0 also count, and substrings originated from different positions in S are distinguished, even if they are equal as strings or integers.

Compute this count to help Takahashi.

Constraints

1 \leq N \leq 2 \times 10^5

S consists of digits.

|S| = N

2 \leq P \leq 10000

P is a prime number.

Input

Input is given from Standard Input in the following format:

N P
S

Output

Print the number of non-empty (contiguous) substrings of S that are divisible by P when regarded as an integer written in base ten.

Sample Input 1

4 3
3543

Sample Output 1

6

Here S = 3543. There are ten non-empty (contiguous) substrings of S:

3: divisible by 3.

35: not divisible by 3.

354: divisible by 3.

3543: divisible by 3.

5: not divisible by 3.

54: divisible by 3.

543: divisible by 3.

4: not divisible by 3.

43: not divisible by 3.

3: divisible by 3.

Six of these are divisible by 3, so print 6.

Sample Input 2

4 2
2020

Sample Output 2

10

Here S = 2020. There are ten non-empty (contiguous) substrings of S, all of which are divisible by 2, so print 10.

Note that substrings beginning with a 0 also count.

Sample Input 3

20 11
33883322005544116655

Sample Output 3

68

Solution in C# (Mono 4.6.2.0) (judge verdict: Runtime Error)

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

namespace CF
{
    class Program
    {
        // https://codeforces.com/contest/ + ContestId
        // ReSharper disable All  d 
        static void Main(string[] args)
        {
            var o = Console.ReadLine().Split().Select(int.Parse).ToList();
            int N = o[0], P = o[1];
            string S = Console.ReadLine();
            var br = 0;
            var subCount = (N * N) - 1;
            var bits = 1 << N;

            for (int i = 0; i < subCount-1; i++) //15
            {
                string s = string.Empty;

                for (int j = 0; j < N; j++)
                {
                    if(((i >> j) & 1) == 1)
                    {
                        s += S[j]; // 35
                    }
                }

                // 35
                if (s == "")
                    continue;

                int res = int.Parse(s);

                if (res == 0)
                    continue;

                if (res % P == 0)
                {
                    Console.WriteLine(s);
                    br++;
                }
                    

            }

            Console.WriteLine(br);
            
        }

    }
}