Language: C++

// yukicoder@csharp

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Runtime.CompilerServices;
//using System.Web.UI;
using Debug = System.Diagnostics.Debug;
// using System.Drawing.Primitives;
//using System.Drawing;
using System.Windows;
using System.Numerics;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            new Solver().Solve();
        }
    }

    //class Cout {
    //    public static Cout operator >>(
    //        Cout a, int b)
    //    {
    //        Console.WriteLine(b);
    //        return a;
    //    }
    //    //public void Cout(long a) { Console.WriteLine(a); }
    //    //public void Cout(double a) { Console.WriteLine(a); }
    //}

    class GeneralPurposeClass {
        //public const double inf = double.PositiveInfinity;
        public const long inf = 1L << 50;
        public readonly TextWriter error = Console.Error;

        public void Rep(long n_, Action<int> action)
        {
            for (int i = 0; i < n_; i++)
            {
                action(i);
            }
        }

        public void Rep2(int a, long n_, Action<int> action)
        {
            for (int i = a; i < n_; i++)
            {
                action(i);
            }
        }

        public string ReadLine()
        {
            return Console.ReadLine();
        }

        public string ReadNext()
        {
            var s = "";
            while (true)
            {
                var c = Console.Read();
                if (c != ' ' && c != '\n' && c != '\r')
                {
                    s += (char)c;
                    break;
                }
            }
            while (true)
            {
                var c = Console.Read();
                if (c == ' ' || c == '\n' || c == '\r') break;
                s += (char)c;
            }
            return s;
        }

        public long ReadLong()
        {
            return Stol(ReadNext());
        }

        public long Stol(string s)
        {
            return long.Parse(s);
        }

        public static void Write<T>(T a)
            where T : IComparable
        { Console.Write(a); }

        public static void WriteL<T>(T a)
            where T : IComparable
        { Console.WriteLine(a); }
    }

    class Solver : GeneralPurposeClass
    {
        public void Solve()
        {
            var n = ReadLong();
            //WriteL("n: " + n);

            var a = 0;
            Rep2(1, 10, (i) =>
            {
                if (n % i == 0) a = i;
            });
            var b = n / a;
            //WriteL("a: " + a);
            //WriteL("b: " + b);
            var c = 1 <= a && a <= 9 
                && 1 <= b && b <= 9;
            WriteL(c ? "Yes" : "No");
        }
    }
}


Compiler output:
a.cc:3:7: error: expected nested-name-specifier before 'System'
    3 | using System;
      |       ^~~~~~
a.cc:4:7: error: expected nested-name-specifier before 'System'
    4 | using System.Collections.Generic;
      |       ^~~~~~
a.cc:5:7: error: expected nested-name-specifier before 'System'
    5 | using System.Linq;
      |       ^~~~~~
a.cc:6:7: error: expected nested-name-specifier before 'System'
    6 | using System.Text;
      |       ^~~~~~
a.cc:7:7: error: expected nested-name-specifier before 'System'
    7 | using System.Threading.Tasks;
      |       ^~~~~~
a.cc:8:7: error: expected nested-name-specifier before 'System'
    8 | using System.IO;
      |       ^~~~~~
a.cc:9:7: error: expected nested-name-specifier before 'System'
    9 | using System.Runtime.CompilerServices;
      |       ^~~~~~
a.cc:11:15: error: 'System' does not name a type
   11 | using Debug = System.Diagnostics.Debug;
      |               ^~~~~~
a.cc:14:7: error: expected nested-name-specifier before 'System'
   14 | using System.Windows;
      |       ^~~~~~
a.cc:15:7: error: expected nested-name-specifier before 'System'
   15 | using System.Numerics;
      |       ^~~~~~
a.cc:21:26: error: 'string' has not been declared
   21 |         static void Main(string[] args)
      |                          ^~~~~~
a.cc:21:35: error: expected ',' or '...' before 'args'
   21 |         static void Main(string[] args)
      |                                   ^~~~
a.cc:25:6: error: expected ';' after class definition
   25 |     }
      |      ^
      |      ;
a.cc: In static member function 'static void ConsoleApp1::Program::Main(int*)':
a.cc:23:17: error: expected type-specifier before 'Solver'
   23 |             new Solver().Solve();
      |                 ^~~~~~
a.cc: At global scope:
a.cc:40:15: error: expected ':' before 'const'
   40 |         public const long inf = 1L << 50;
      |               ^~~~~~
      |               :
a.cc:41:15: error: expected ':' before 'readonly'
   41 |         public readonly TextWriter error = Console.Error;
      |               ^~~~~~~~~
      |               :
a.cc:41:16: error: 'readonly' does not name a type
   41 |         public readonly TextWriter error = Console.Error;
      |                ^~~~~~~~
a.cc:43:15: error: expected ':' before 'void'
   43 |         public void Rep(long n_, Action<int> action)
      |               ^~~~~
      |               :
a.cc:43:34: error: 'Action' has not been declared
   43 |         public void Rep(long n_, Action<int> action)
      |                                  ^~~~~~
a.cc:43:40: error: expected ',' or '...' before '<' token
   43 |         public void Rep(long n_, Action<int> action)
      |                                        ^
a.cc:51:15: error: expected ':' before 'void'
   51 |         public void Rep2(int a, long n_, Action<int> action)
      |               ^~~~~
      |               :
a.cc:51:42: error: 'Action' has not been declared
   51 |         public void Rep2(int a, long n_, Action<int> action)
      |                                          ^~~~~~
a.cc:51:48: error: expected ',' or '...' before '<' token
   51 |         public void Rep2(int a, long n_, Action<int> action)
      |                                                ^
a.cc:59:15: error: expected ':' before 'string'
   59 |         public string ReadLine()
      |               ^~~~~~~
      |               :
a.cc:59:16: error: 'string' does not name a type
   59 |         public string ReadLine()
      |                ^~~~~~
a.cc:64:15: error: expected ':' before 'string'
   64 |         public string ReadNext()
      |               ^~~~~~~
      |               :
a.cc:64:16: error: 'string' does not name a type
   64 |         public string ReadNext()
      |                ^~~~~~
a.cc:85:15: error: expected ':' before 'long'
   85 |         public long ReadLong()
      |               ^~~~~
      |               :
a.cc:90:15: error: expected ':' before 'long'
   90 |         public long Stol(string s)
      |               ^~~~~
      |               :
a.cc:90:26: error: 'string' has not been declared
   90 |         public long Stol(string s)
      |                          ^~~~~~
a.cc:95:15: error: expected ':' before 'static'
   95 |         public static void Write<T>(T a)
      |               ^~~~~~~
      |               :
a.cc:95:28: error: variable or field 'Write' declared void
   95 |         public static void Write<T>(T a)
      |                            ^~~~~
a.cc:95:28: error: expected ';' at end of member declaration
   95 |         public static void Write<T>(T a)
      |                            ^~~~~
      |                                 ;
a.cc:95:33: error: expected unqualified-id before '<' token
   95 |         public static void Write<T>(T a)
      |                                 ^
a.cc:99:15: error: expected ':' before 'static'
   99 |         public static void WriteL<T>(T a)
      |               ^~~~~~~
      |               :
a.cc:99:28: error: variable or field 'WriteL' declared void
   99 |         public static void WriteL<T>(T a)
      |                            ^~~~~~
a.cc:99:28: error: expected ';' at end of member declaration
   99 |         public static void WriteL<T>(T a)
      |                            ^~~~~~
      |                                  ;
a.cc:99:34: error: expected unqualified-id before '<' token
   99 |         public static void WriteL<T>(T a)
      |                                  ^
a.cc:102:6: error: expected ';' after class definition
  102 |     }
      |      ^
      |      ;
a.cc: In member function 'void ConsoleApp1::GeneralPurposeClass::Rep(long int, int)':
a.cc:47:17: error: 'action' was not declared in this scope
   47 |                 action(i);
      |                 ^~~~~~
a.cc: In member function 'void ConsoleApp1::GeneralPurposeClass::Rep2(int, long int, int)':
a.cc:55:17: error: 'action' was not declared in this scope
   55 |                 action(i);
      |                 ^~~~~~
a.cc: In member function 'long int ConsoleApp1::GeneralPurposeClass::ReadLong()':
a.cc:87:25: error: 'ReadNext' was not declared in this scope
   87 |             return Stol(ReadNext());
      |                         ^~~~~~~~
a.cc: In member function 'long int ConsoleApp1::GeneralPurposeClass::Stol(int)':
a.cc:92:20: error: expected primary-expression before 'long'
   92 |             return long.Parse(s);
      |                    ^~~~
a.cc:92:20: error: expected ';' before 'long'
a.cc:92:24: error: expected unqualified-id before '.' token
   92 |             return long.Parse(s);
      |                        ^
a.cc: At global scope:
a.cc:106:15: error: expected ':' before 'void'
  106 |         public void Solve()
      |               ^~~~~
      |               :
a.cc:123:6: error: expected ';' after class definition
  123 |     }
      |      ^
      |      ;
a.cc: In member function 'void ConsoleApp1::Solver::Solve()':
a.cc:108:13: error: 'var' was not declared in this scope
  108 |             var n = ReadLong();
      |             ^~~
a.cc:111:17: error: expected ';' before 'a'
  111 |             var a = 0;
      |                 ^
a.cc:112:26: error: 'i' was not declared in this scope
  112 |             Rep2(1, 10, (i) =>
      |                          ^
a.cc:112:30: error: expected primary-expression before '>' token
  112 |             Rep2(1, 10, (i) =>
      |                              ^
a.cc:113:13: error: expected primary-expression before '{' token
  113 |             {
      |             ^
a.cc:116:17: error: expected ';' before 'b'
  116 |             var b = n / a;
      |                 ^
a.cc:119:17: error: expected ';' before 'c'
  119 |             var c = 1 <= a && a <= 9
      |                 ^
a.cc:121:20: error: 'c' was not declared in this scope
  121 |             WriteL(c ? "Yes" : "No");
      |                    ^
a.cc:121:13: error: 'WriteL' was not declared in this scope
  121 |             WriteL(c ? "Yes" : "No");
      |             ^~~~~~