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.Collections.Generic;
using System.Runtime.Remoting.Metadata.W3cXsd2001;

namespace Program
{
    public class Program
    {
        public static void Main(String[] args)
        {
            char[] s = toCharArray();
            Dictionary<char, int> dist = new Dictionary<char, int>();
            Dictionary<char, List<int>> prepoint = new Dictionary<char,List<int>>();
            for (char c = 'a'; c <= 'z'; c++)
            {
                dist.Add(c, int.MaxValue);
                prepoint.Add(c, new List<int>());
            }
            for (int i = 0; i < s.Length; i++)
            {
                char c = s[i];

                if (prepoint[c].Count >= 1)
                {
                    int minDist = dist[c];
                    List<int> points = prepoint[c];
                    for (int j = 0; j < points.Count; j++)
                    {
                        if (minDist > i - points[j])
                        {
                            minDist = i - points[j];
                        }
                    }

                    dist[c] = minDist;
                }

                prepoint[c].Add(i);
            }

            int targetDist = int.MaxValue;
            char target = ' ';
            for (char c = 'a'; c <= 'z'; c++)
            {
                if (targetDist > dist[c])
                {
                    target = c;
                    targetDist = dist[c];
                }
            }

            if (targetDist == int.MaxValue)
            {
                Console.WriteLine(0);
                return;
            }

            int start, end;
            List<int> tpoints = prepoint[target];
            for (int i = 0; i < tpoints.Count-1; i++)
            {
                for (int j = i + 1; j < tpoints.Count; j++)
                {
                    if (j - i == targetDist)
                    {
                        Console.WriteLine((i + 1) + " " + (j + 1));
                        return;
                    }
                }
            }
        }

        static int nextInt()
        {
            return int.Parse(Console.ReadLine());
        }

        static char[] toCharArray()
        {
            return Console.ReadLine().ToCharArray();
        }
    }
}