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 PyPy3 (2.4.0) (judge verdict: Wrong Answer)

import sys

# import bisect
# from collections import Counter, deque, defaultdict
# import copy
# from heapq import heappush, heappop, heapify
# from fractions import gcd
# import itertools
# from operator import attrgetter, itemgetter

# import math

# from numba import jit

# from scipy import
# import numpy as np
# import networkx as nx

# import matplotlib.pyplot as plt

readline = sys.stdin.readline
MOD = 10 ** 9 + 7
INF = float('INF')
sys.setrecursionlimit(10 ** 5)


def main():
    n, p = list(map(int, readline().split()))
    s = input()

    ans = 0

    if p == (2 or 5):
        for i in range(n):
            if int(s[i]) % p == 0:
                ans += (i + 1)
    else:
        from collections import Counter
        m = Counter()
        m[0] = 1
        for i in range(n):
            num = int(s[n - i - 1:n])
            ans += m[num % p]
            m[num % p] += 1

    print(ans)

if __name__ == '__main__':
    main()