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: Accepted)

package main
import (
  "fmt"
)
func main() {
  var s string
  fmt.Scan(&s)
  f, l := -1, -1
  var secondPrevChar, prevChar rune
  for i, char := range s {
    if i == 0 {
      prevChar = char
      continue
    }
    if i == 1 {
      if char == prevChar {
        f = 1
        l = 2
        break
      }
      secondPrevChar = prevChar
      prevChar = char
      continue
    }
    if char == prevChar {
      f = i
      l = i+1
      break
    }
    if char == secondPrevChar {
      f = i-1
      l = i+1
      break
    }
    secondPrevChar = prevChar
    prevChar = char
  }
  fmt.Println(f, l)
}