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: Accepted)

import Data.List (findIndex)
import Data.Maybe (maybe)

main = putStrLn =<< solve <$> getLine

solve :: String -> String
solve s = unwords [show a, show b] where
    (a, b) = solve' s

solve' :: String -> (Int, Int)
solve' = maybe (-1, -1) (\(a, b) -> (a + 1, b + 1)) . findUnBalanceIndex

findUnBalanceIndex :: String -> Maybe (Int, Int)
findUnBalanceIndex [a, b]
    | a == b = Just (0, 1)
    | otherwise = Nothing
findUnBalanceIndex s = fmap (\i -> (i, i + 2)) . findIndex isUnbalance $ window' s

isUnbalance :: String -> Bool
isUnbalance [a, b, c] = a == b || b == c || c == a
isUnbalance s = error $ "length s must be 3 but " ++ (show $ length s)

window' :: [a] -> [[a]]
window' [] = []
window' [a] = []
window' [a, b] = []
window' xs = take 3 xs : window' (tail xs)