Language: C++

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Xml.Xsl;
using static System.Math;

namespace CSharpSpiral {
	class Program {
		static void Main(string[] args) {
			var sw = new StreamWriter(Console.OpenStandardOutput()) {
				AutoFlush=
#if DEBUG
			true
#else
			false
#endif
			};
			Console.SetOut(sw);
			new Program().Solve(new ConsoleInput(
#if DEBUG
			new StreamReader("../../../inputData.txt")
#else
			Console.In
#endif
			, ' '));
			Console.Out.Flush();
		}
		public void Solve(ConsoleInput cin) {
			var line = cin.ReadLine;
			Console.WriteLine(line[2]==line[3]&&line[4]==line[5]?"Yes":"No");
		}
	}
	static class ExtendClass {
		public static void Swap<T>(this T[] A, int x, int y) {
			var tmp = A[x];
			A[x]=A[y];
			A[y]=tmp;
		}
		public static string Join<T>(this IEnumerable<T> X, string separator = " ") => string.Join(separator, X);
		public static IEnumerable<int> Indices<T>(this T[] X) => Enumerable.Range(0, X.Length);
		public static IEnumerable<int> Indices<T>(this T[,] X, int dim)
			=> Enumerable.Range(0, X.GetLength(dim));
		public static string Join<T>(this T[,] X, string separatorD2 = ",", string separatorD1 = "\n")
			=> X.Indices(0).Select(
				i => X.Indices(1).Select(j => X[i, j]).Join(separatorD2)
			).Join(separatorD1);
	}
	class ConsoleInput {
		private readonly TextReader _stream;
		private readonly char _separator = ' ';
		private readonly Queue<string> inputStream;
		public ConsoleInput(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; }
		public double[] ReadDoubleArray(long N) { var ret = new double[N]; for(long i = 0; i<N; ++i) ret[i]=ReadDouble; return ret; }
		public bool isEOF {
			get { return _stream.Peek()==-1; }
		}
	}
}

Compiler output:
a.cc:1:7: error: expected nested-name-specifier before 'System'
    1 | using System;
      |       ^~~~~~
a.cc:2:7: error: expected nested-name-specifier before 'System'
    2 | using System.Collections.Generic;
      |       ^~~~~~
a.cc:3:7: error: expected nested-name-specifier before 'System'
    3 | using System.IO;
      |       ^~~~~~
a.cc:4:7: error: expected nested-name-specifier before 'System'
    4 | using System.Linq;
      |       ^~~~~~
a.cc:5:7: error: expected nested-name-specifier before 'System'
    5 | using System.Text;
      |       ^~~~~~
a.cc:6:7: error: expected nested-name-specifier before 'System'
    6 | using System.Text.RegularExpressions;
      |       ^~~~~~
a.cc:7:7: error: expected nested-name-specifier before 'System'
    7 | using System.Xml.Xsl;
      |       ^~~~~~
a.cc:8:7: error: expected nested-name-specifier before 'static'
    8 | using static System.Math;
      |       ^~~~~~
a.cc:12:34: error: 'string' has not been declared
   12 |                 static void Main(string[] args) {
      |                                  ^~~~~~
a.cc:12:43: error: expected ',' or '...' before 'args'
   12 |                 static void Main(string[] args) {
      |                                           ^~~~
a.cc:31:23: error: expected ':' before 'void'
   31 |                 public void Solve(ConsoleInput cin) {
      |                       ^~~~~
      |                       :
a.cc:31:35: error: 'ConsoleInput' has not been declared
   31 |                 public void Solve(ConsoleInput cin) {
      |                                   ^~~~~~~~~~~~
a.cc:35:10: error: expected ';' after class definition
   35 |         }
      |          ^
      |          ;
a.cc: In static member function 'static void CSharpSpiral::Program::Main(int*)':
a.cc:13:25: error: 'var' was not declared in this scope
   13 |                         var sw = new StreamWriter(Console.OpenStandardOutput()) {
      |                         ^~~
a.cc:21:25: error: 'Console' was not declared in this scope
   21 |                         Console.SetOut(sw);
      |                         ^~~~~~~
a.cc:21:40: error: 'sw' was not declared in this scope
   21 |                         Console.SetOut(sw);
      |                                        ^~
a.cc:22:38: error: expected ';' before '.' token
   22 |                         new Program().Solve(new ConsoleInput(
      |                                      ^
a.cc: In member function 'void CSharpSpiral::Program::Solve(int)':
a.cc:32:25: error: 'var' was not declared in this scope
   32 |                         var line = cin.ReadLine;
      |                         ^~~
a.cc:33:25: error: 'Console' was not declared in this scope
   33 |                         Console.WriteLine(line[2]==line[3]&&line[4]==line[5]?"Yes":"No");
      |                         ^~~~~~~
a.cc:33:43: error: 'line' was not declared in this scope
   33 |                         Console.WriteLine(line[2]==line[3]&&line[4]==line[5]?"Yes":"No");
      |                                           ^~~~
a.cc: At global scope:
a.cc:37:23: error: expected ':' before 'static'
   37 |                 public static void Swap<T>(this T[] A, int x, int y) {
      |                       ^~~~~~~
      |                       :
a.cc:37:36: error: variable or field 'Swap' declared void
   37 |                 public static void Swap<T>(this T[] A, int x, int y) {
      |                                    ^~~~
a.cc:37:36: error: expected ';' at end of member declaration
   37 |                 public static void Swap<T>(this T[] A, int x, int y) {
      |                                    ^~~~
      |                                        ;
a.cc:37:40: error: expected unqualified-id before '<' token
   37 |                 public static void Swap<T>(this T[] A, int x, int y) {
      |                                        ^
a.cc:42:23: error: expected ':' before 'static'
   42 |                 public static string Join<T>(this IEnumerable<T> X, string separator = " ") => string.Join(separator, X);
      |                       ^~~~~~~
      |                       :
a.cc:42:31: error: 'string' does not name a type
   42 |                 public static string Join<T>(this IEnumerable<T> X, string separator = " ") => string.Join(separator, X);
      |                               ^~~~~~
a.cc:43:23: error: expected ':' before 'static'
   43 |                 public static IEnumerable<int> Indices<T>(this T[] X) => Enumerable.Range(0, X.Length);
      |                       ^~~~~~~
      |                       :
a.cc:43:31: error: 'IEnumerable' does not name a type
   43 |                 public static IEnumerable<int> Indices<T>(this T[] X) => Enumerable.Range(0, X.Length);
      |                               ^~~~~~~~~~~
a.cc:44:23: error: expected ':' before 'static'
   44 |                 public static IEnumerable<int> Indices<T>(this T[,] X, int dim)
      |                       ^~~~~~~
      |                       :
a.cc:44:31: error: 'IEnumerable' does not name a type
   44 |                 public static IEnumerable<int> Indices<T>(this T[,] X, int dim)
      |                               ^~~~~~~~~~~
a.cc:46:23: error: expected ':' before 'static'
   46 |                 public static string Join<T>(this T[,] X, string separatorD2 = ",", string separatorD1 = "\n")
      |                       ^~~~~~~
      |                       :
a.cc:46:31: error: 'string' does not name a type
   46 |                 public static string Join<T>(this T[,] X, string separatorD2 = ",", string separatorD1 = "\n")
      |                               ^~~~~~
a.cc:50:10: error: expected ';' after class definition
   50 |         }
      |          ^
      |          ;
a.cc:36:9: error: a storage class can only be specified for objects and functions
   36 |         static class ExtendClass {
      |         ^~~~~~
a.cc:52:24: error: expected ':' before 'readonly'
   52 |                 private readonly TextReader _stream;
      |                        ^~~~~~~~~
      |                        :
a.cc:52:25: error: 'readonly' does not name a type
   52 |                 private readonly TextReader _stream;
      |                         ^~~~~~~~
a.cc:53:24: error: expected ':' before 'readonly'
   53 |                 private readonly char _separator = ' ';
      |                        ^~~~~~~~~
      |                        :
a.cc:53:25: error: 'readonly' does not name a type
   53 |                 private readonly char _separator = ' ';
      |                         ^~~~~~~~
a.cc:54:24: error: expected ':' before 'readonly'
   54 |                 private readonly Queue<string> inputStream;
      |                        ^~~~~~~~~
      |                        :
a.cc:54:25: error: 'readonly' does not name a type
   54 |                 private readonly Queue<string> inputStream;
      |                         ^~~~~~~~
a.cc:55:23: error: expected ':' before 'ConsoleInput'
   55 |                 public ConsoleInput(TextReader stream, char separator = ' ') {
      |                       ^~~~~~~~~~~~~
      |                       :
a.cc:55:47: error: expected ')' before 'stream'
   55 |                 public ConsoleInput(TextReader stream, char separator = ' ') {
      |                                    ~          ^~~~~~~
      |                                               )
a.cc:60:23: error: expected ':' before 'string'
   60 |                 public string Read {
      |                       ^~~~~~~
      |                       :
a.cc:60:24: error: 'string' does not name a type
   60 |                 public string Read {
      |                        ^~~~~~
a.cc:69:23: error: expected ':' before 'string'
   69 |                 public string ReadLine { get { return _stream.ReadLine(); } }
      |                       ^~~~~~~
      |                       :
a.cc:69:24: error: 'string' does not name a type
   69 |                 public string ReadLine { get { return _stream.ReadLine(); } }
      |                        ^~~~~~
a.cc:70:23: error: expected ':' before 'int'
   70 |                 public int ReadInt { get { return int.Parse(Read); } }
      |                       ^~~~
      |                       :
a.cc:70:70: error: expected ';' at end of member declaration
   70 |                 public int ReadInt { get { return int.Parse(Read); } }
      |                                                                      ^
      |                                                                       ;
a.cc:71:23: error: expected ':' before 'long'
   71 |                 public long ReadLong { get { return long.Parse(Read); } }
      |                       ^~~~~
      |                       :
a.cc:71:73: error: expected ';' at end of member declaration
   71 |                 public long ReadLong { get { return long.Parse(Read); } }
      |                                                                         ^
      |                                                                          ;
a.cc:72:23: error: expected ':' before 'double'
   72 |                 public double ReadDouble { get { return double.Parse(Read); } }
      |                       ^~~~~~~
      |                       :
a.cc:72:79: error: expected ';' at end of member declaration
   72 |                 public double ReadDouble { get { return double.Parse(Read); } }
      |                                                                               ^
      |                                                                                ;
a.cc:73:23: error: expected ':' before 'string'
   73 |                 public string[] ReadStrArray(long N) {
      |                       ^~~~~~~
      |                       :
a.cc:73:24: error: 'string' does not name a type
   73 |                 public string[] ReadStrArray(long N) {
      |                        ^~~~~~
a.cc:79:23: error: expected ':' before 'int'
   79 |                 public int[] ReadIntArray(long N) { var ret = new int[N]; for(long i = 0; i<N; ++i) ret[i]=ReadInt; return ret; }
      |                       ^~~~
      |                       :
a.cc:79:27: error: expec