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 Go (1.14.1) (judge verdict: Wrong Answer)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func scanText() string {
	sc.Scan()
	return sc.Text()
}

func reverse(s string) (result string) {
	for _, v := range s {
		result = string(v) + result
	}
	return
}

var sc = bufio.NewScanner(os.Stdin)

func main() {
	s := reverse(scanText())
	cnts := map[int]int{}
	sum := 0
	d := 1

	cnts[0] = 1
	for _, c := range s {
		cn, _ := strconv.Atoi(string(c))
		cn *= d
		sum += cn
		sum %= 2019
		d *= 10
		d %= 2019
		cnts[sum]++
	}

	ans := 0
	for _, cnt := range cnts {
		ans += cnt * (cnt - 1) / 2
	}
	fmt.Println(ans)
}