Problem:
Score : 100 points

Problem Statement

On some day in January 2018, Takaki is writing a document. The document has a column where the current date is written in yyyy/mm/dd format. For example, January 23, 2018 should be written as 2018/01/23.

After finishing the document, she noticed that she had mistakenly wrote 2017 at the beginning of the date column. Write a program that, when the string that Takaki wrote in the date column, S, is given as input, modifies the first four characters in S to 2018 and prints it.

Constraints

S is a string of length 10.

The first eight characters in S are 2017/01/.

The last two characters in S are digits and represent an integer between 1 and 31 (inclusive).

Input

Input is given from Standard Input in the following format:

S

Output

Replace the first four characters in S with 2018 and print it.

Sample Input 1

2017/01/07

Sample Output 1

2018/01/07

Sample Input 2

2017/01/31

Sample Output 2

2018/01/31

Solution in C# (Mono 4.6.2.0) (judge verdict: Runtime Error)

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

namespace PastQuestions
{
    class Program
    {
        static void Main(string[] args)
        {
            new Program().Solve(new Input(Console.In));
        }

        public void Solve(Input input)
        {
            var answer = Solve2(input);
            Console.Write($"{answer[0]} {answer[1]} {answer[2]}");
        }
        public int[] Solve2(Input input)
        {
            var n = input.ReadInt;
            var y = input.ReadInt;

            var answer = new int[3] { -1, -1, -1 };
            for (var i = 0; i <= n; i++)
            {
                var total = 10000 * i;
                for (var j = 0; j <= n - i; j++)
                {
                    total += 5000 * j;
                    var temp = total;
                    for (var k = 0; k <= n - i - j; k++)
                    {
                        total = temp;
                        total += 1000 * k;
                        if (y == total)
                        {
                            answer[0] = i;
                            answer[1] = j;
                            answer[2] = k;
                            return answer;
                        }
                    }
                }
            }
            return answer;
        }
    }

    public class Input
    {
        private TextReader Stream { get; }
        private char Separator { get; }
        private Queue<string> InputStream { get; }

        public Input(TextReader stream, char separator = ' ')
        {
            Stream = stream;
            Separator = separator;
            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 => Stream.ReadLine();
        public int ReadInt => int.Parse(Read);
        public long ReadLong => long.Parse(Read);
        public double ReadDouble => double.Parse(Read);
        public int[] ReadIntArray => Stream.ReadLine().Split(Separator).Select(i => int.Parse(i)).ToArray();
        public long[] ReadLongArray => Stream.ReadLine().Split(Separator).Select(l => long.Parse(l)).ToArray();
    }
}