Problem:
Score : 100 points

Problem Statement

Given a lowercase English letter c, determine whether it is a vowel. Here, there are five vowels in the English alphabet: a, e, i, o and u.

Constraints

c is a lowercase English letter.

Input

The input is given from Standard Input in the following format:

c

Output

If c is a vowel, print vowel. Otherwise, print consonant.

Sample Input 1

a

Sample Output 1

vowel

Since a is a vowel, print vowel.

Sample Input 2

z

Sample Output 2

consonant

Sample Input 3

s

Sample Output 3

consonant

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

using System;
using System.Text;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using static System.Console;
using static System.Math;

namespace AtCoder
{
    public class Program
    {
        public static void Main(string[] args)
        {
            new Program().Solve(new ConsoleInput(Console.In,' '));
        }

        public void Solve(ConsoleInput cin)
        {
            string S = cin.ReadLine;
            var words = new string[] {"dream","eraser","erase"};
            var checkWords = new string[] {"eraser","erase","er"};
            bool flgForCheck = false;

            for(int i=0; i<S.Length;){
              	flgForCheck = false;
                foreach (string word in words)
                {
                  	if((i + word.Length) > S.Length) continue;
                    if(S.Substring(i,word.Length) == word){
                        i += word.Length;
                        flgForCheck = true;
                        if(word == "dream"){
                            i = Check(i,S,checkWords);
                        }
                        break;
                    }
                }
                if(!flgForCheck)break;
            }

            if(flgForCheck) WriteLine("YES");
            else WriteLine("NO");
        }

        int Check(int i , string S,string[] array){
            foreach(string word in array){
                if((i + word.Length) > S.Length) continue;
                if(S.Substring(i,word.Length) == word){
                    i += word.Length;
                    break;
                }
            }
            return i;
        }
    }


    public class ConsoleInput
    {
        private readonly System.IO.TextReader _stream;
        private char _separator = ' ';
        private Queue<string> inputStream;
        public ConsoleInput(System.IO.TextReader stream,char separator = ' ')
        {
            this._separator = separator;
            this._stream = stream;
            inputStream = new Queue<string>();
        }

        public string Read
        {
            get
            {
                if(inputStream.Count != 0) return inputStream.Dequeue();
                string[] tmp = _stream.ReadLine().Split(_separator);
                for(int i = 0;i < tmp.Length;i++)
                    inputStream.Enqueue(tmp[i]);
                return inputStream.Dequeue();
            }
        }

        
        public string ReadLine { get { return _stream.ReadLine(); }}
        public int ReadInt { get { return int.Parse(Read); }}
        public long ReadLong { get { return long.Parse(Read); }}
        public double ReadDouble { get { return double.Parse(Read); }}
        public string[] ReadStrArray(long N) { var ret = new string[N]; for (long i = 0; i < N; ++i) ret[i] = Read; return ret;}
        public int[] ReadIntArray(long N) { var ret = new int[N]; for (long i = 0; i < N; ++i) ret[i] = ReadInt; return ret;}
        public long[] ReadLongArray(long N) { var ret = new long[N]; for (long i = 0; i < N; ++i) ret[i] = ReadLong; return ret;}
    }

}