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 Haskell (GHC 7.10.3) (judge verdict: Time Limit Exceeded)

import Data.Bifunctor (bimap, first, second)
import Data.Foldable  (and, or, product, sum)
import Data.Function
import Data.Monoid    ((<>))

import qualified Data.List as L

import Control.Applicative
import Control.Monad

main :: IO ()
main = do
    s <- getLine
    answer $ solve s

type Answer = (Int, Int)
answer :: Answer -> IO ()
answer (a, b) = putStrLn $ show a ++ " " ++ show b

solve :: String -> Answer
solve s =
  let
    l       = L.length s
    substrs = s
        & L.init . L.tails
        & L.concatMap (L.tail . L.inits)
        & L.zip [(a, b) | a <- [1 .. l], b <- [a .. l]]
  in case L.map fst $ L.filter (unbalanced . snd) substrs of
    []      -> (-1, -1)
    range:_ -> range

unbalanced :: String -> Bool
unbalanced s =
  let
    nummode = L.maximum . L.map L.length . L.group $ L.sort s
    l       = L.length s
  in
    l >= 2 && l - nummode < nummode