Problem:
Score : 400 points

Problem Statement

Given a string t, we will call it unbalanced if and only if the length of t is at least 2, and more than half of the letters in t are the same. For example, both voodoo and melee are unbalanced, while neither noon nor a is.

You are given a string s consisting of lowercase letters. Determine if there exists a (contiguous) substring of s that is unbalanced. If the answer is positive, show a position where such a substring occurs in s.

Constraints

2 ≦ |s| ≦ 10^5

s consists of lowercase letters.

Partial Score

200 points will be awarded for passing the test set satisfying 2 ≦ N ≦ 100.

Input

The input is given from Standard Input in the following format:

s

Output

If there exists no unbalanced substring of s, print -1 -1.

If there exists an unbalanced substring of s, let one such substring be s_a s_{a+1} ... s_{b} (1 ≦ a < b ≦ |s|), and print a b. If there exists more than one such substring, any of them will be accepted.

Sample Input 1

needed

Sample Output 1

2 5

The string s_2 s_3 s_4 s_5 = eede is unbalanced. There are also other unbalanced substrings. For example, the output 2 6 will also be accepted.

Sample Input 2

atcoder

Sample Output 2

-1 -1

The string atcoder contains no unbalanced substring.

Solution in Go (1.6) (judge verdict: Wrong Answer)

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
)

const N = 4

func isUnbalance(bytes []byte, idx int) bool {
	if len(bytes) < idx+N {
		return false
	}

	chars := [26]int{}

	for _, c := range bytes[idx : idx+N] {
		//c := bytes[idx+i]
		chars[uint(c)-97]++
	}

	s := false
	for _, v := range chars {
		if v == 3 {
			return true
		}
		if v == 2 && !s {
			s = true
		}
		if v == 2 && s {
			s = false
		}
	}

	return s
}

func main() {
	bytes, err := ioutil.ReadAll(os.Stdin)
	if err != nil {
		log.Fatal(err)
	}
	bytes = bytes[0 : len(bytes)-1]

	m := len(bytes) - N
	for l := 0; l <= m; l++ {
		b := isUnbalance(bytes, l)
		if b {
			fmt.Printf("%d %d\n", l+1, l+3+1)
			return
		}
	}
	fmt.Printf("-1 -1\n")
}