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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Linq;
using System.IO;
using System.Text;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;

class Program{
    static void Main(){
        string s = Console.ReadLine();
        int[] cnt = new int[30];
        for(int i = 0; i < s.Length; i++){
            cnt[s[i] - 'a']++;
        }
        char most = (char)(cnt.Select((value, index) => new{V = value, I = index})
                             .Aggregate((max, next) => max = max.V < next.V ? next : max)
                             .I + (int)'a');
        int b = s.IndexOf(most);
        int e = -1;
        bool found = false;
        while(!found && b != - 1){
            for(e = b + 2; e < s.Length; e++){
                if(Unbalance(s.Substring(b, e - b + 1))){
                    found = true;
                    b++;
                    e++;
                    break;
                }
            }
            if(!found) b = s.IndexOf(most, b + 1);
        }
        if(!found){
            b = -1;
            e = -1;
        }
        Console.WriteLine("{0} {1}", b, e);
    }

    static bool Unbalance(string str){
        int[] cnt = new int[30];
        for(int i = 0; i < str.Length; i++){
            cnt[str[i] - 'a']++;
        }
        if(cnt.Max() > str.Length / 2) return true;
        else return false;
    }
}