Problem:
Score : 400 points

Problem Statement

Given is a string S consisting of digits from 1 through 9.

Find the number of pairs of integers (i,j) (1 ≤ i ≤ j ≤ |S|) that satisfy the following condition:

Condition: In base ten, the i-th through j-th characters of S form an integer that is a multiple of 2019.

Constraints

1 ≤ |S| ≤ 200000

S is a string consisting of digits from 1 through 9.

Input

Input is given from Standard Input in the following format:

S

Output

Print the number of pairs of integers (i,j) (1 ≤ i ≤ j ≤ |S|) that satisfy the condition.

Sample Input 1

1817181712114

Sample Output 1

3

Three pairs - (1,5), (5,9), and (9,13) - satisfy the condition.

Sample Input 2

14282668646

Sample Output 2

2

Sample Input 3

2119

Sample Output 3

0

No pairs satisfy the condition.

Solution in Haskell (GHC 8.8.3) (judge verdict: Time Limit Exceeded)

import qualified Data.List as L
import qualified Data.Set as Set

main :: IO ()
main = do
  s <- getLine
  let s1 = (check s) :: [String]
  let s2 = check2 $ map read s1 :: [Int]
  print $ L.length $ ordNub s2

check s = L.filter (\x -> L.length x >= 4) $ ordNub $ L.subsequences s
check2 s = L.filter (\x -> x `mod` 2019 == 0) s

ordNub :: Ord a => [a] -> [a]
ordNub xs = foldr (\x k s -> if Set.member x s
  then k s
  else x : k (Set.insert x s))
  (const []) xs Set.empty