Language: C++

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


class Program
{


    static void Main(string[] args)
    {
        Solve();
    }

    static void Solve()
    {
        Scan sc = new Scan();
        write wr = new write();


        var c = sc.intarr;
        int n = c[0];
        int ans = 0;


        Dictionary<string, int> a= new Dictionary<string, int>();

        for(int i = 0; i < n ; ++i)
        {
            
            string s = sc.str;
            if (a.ContainsKey(s))
            {
                a[s]++;

            }
            else a[s] = 1;
        }
         c = sc.intarr;
        int m = c[0];
        for (int i = 0; i < m; ++i)
        {
            string s = sc.str;
            if (a.ContainsKey(s))
            {
                a[s]--;

            }
        }

        foreach(var x in a)
        {
            ans = Math.Max(ans, x.Value);
        }

        wr.wri(ans);
    }


}
    class Scan
    {
        public string str => Console.ReadLine();

        public string[] strarr => str.Split(' ');

        public long[] longarr => strarr.Select(long.Parse).ToArray();
        public int[] intarr => strarr.Select(int.Parse).ToArray();
        public char[] chararr => strarr.Select(char.Parse).ToArray();


}



class write
{
    public void wri<Type>(Type x)
    {
        Console.WriteLine(x);
    }
}


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.Linq;
      |       ^~~~~~
a.cc:4:7: error: expected nested-name-specifier before 'System'
    4 | using System.Text;
      |       ^~~~~~
a.cc:5:7: error: expected nested-name-specifier before 'System'
    5 | using System.Threading.Tasks;
      |       ^~~~~~
a.cc:12:22: error: 'string' has not been declared
   12 |     static void Main(string[] args)
      |                      ^~~~~~
a.cc:12:31: error: expected ',' or '...' before 'args'
   12 |     static void Main(string[] args)
      |                               ^~~~
a.cc:62:2: error: expected ';' after class definition
   62 | }
      |  ^
      |  ;
a.cc: In static member function 'static void Program::Solve()':
a.cc:19:9: error: 'Scan' was not declared in this scope
   19 |         Scan sc = new Scan();
      |         ^~~~
a.cc:20:9: error: 'write' was not declared in this scope
   20 |         write wr = new write();
      |         ^~~~~
a.cc:23:9: error: 'var' was not declared in this scope
   23 |         var c = sc.intarr;
      |         ^~~
a.cc:24:17: error: 'c' was not declared in this scope
   24 |         int n = c[0];
      |                 ^
a.cc:28:9: error: 'Dictionary' was not declared in this scope
   28 |         Dictionary<string, int> a= new Dictionary<string, int>();
      |         ^~~~~~~~~~
a.cc:28:20: error: 'string' was not declared in this scope
   28 |         Dictionary<string, int> a= new Dictionary<string, int>();
      |                    ^~~~~~
a.cc:28:28: error: expected primary-expression before 'int'
   28 |         Dictionary<string, int> a= new Dictionary<string, int>();
      |                            ^~~
a.cc:33:20: error: expected ';' before 's'
   33 |             string s = sc.str;
      |                    ^
a.cc:34:17: error: 'a' was not declared in this scope
   34 |             if (a.ContainsKey(s))
      |                 ^
a.cc:34:31: error: 's' was not declared in this scope
   34 |             if (a.ContainsKey(s))
      |                               ^
a.cc:41:14: error: 'sc' was not declared in this scope
   41 |          c = sc.intarr;
      |              ^~
a.cc:45:20: error: expected ';' before 's'
   45 |             string s = sc.str;
      |                    ^
a.cc:46:17: error: 'a' was not declared in this scope
   46 |             if (a.ContainsKey(s))
      |                 ^
a.cc:46:31: error: 's' was not declared in this scope
   46 |             if (a.ContainsKey(s))
      |                               ^
a.cc:53:21: error: expected ')' before 'x'
   53 |         foreach(var x in a)
      |                     ^
a.cc:53:16: note: to match this '('
   53 |         foreach(var x in a)
      |                ^
a.cc:53:9: error: 'foreach' was not declared in this scope
   53 |         foreach(var x in a)
      |         ^~~~~~~
a.cc:58:9: error: 'wr' was not declared in this scope
   58 |         wr.wri(ans);
      |         ^~
a.cc: At global scope:
a.cc:65:15: error: expected ':' before 'string'
   65 |         public string str => Console.ReadLine();
      |               ^~~~~~~
      |               :
a.cc:65:16: error: 'string' does not name a type
   65 |         public string str => Console.ReadLine();
      |                ^~~~~~
a.cc:67:15: error: expected ':' before 'string'
   67 |         public string[] strarr => str.Split(' ');
      |               ^~~~~~~
      |               :
a.cc:67:16: error: 'string' does not name a type
   67 |         public string[] strarr => str.Split(' ');
      |                ^~~~~~
a.cc:69:15: error: expected ':' before 'long'
   69 |         public long[] longarr => strarr.Select(long.Parse).ToArray();
      |               ^~~~~
      |               :
a.cc:69:20: error: expected unqualified-id before '[' token
   69 |         public long[] longarr => strarr.Select(long.Parse).ToArray();
      |                    ^
a.cc:70:15: error: expected ':' before 'int'
   70 |         public int[] intarr => strarr.Select(int.Parse).ToArray();
      |               ^~~~
      |               :
a.cc:70:19: error: expected unqualified-id before '[' token
   70 |         public int[] intarr => strarr.Select(int.Parse).ToArray();
      |                   ^
a.cc:71:15: error: expected ':' before 'char'
   71 |         public char[] chararr => strarr.Select(char.Parse).ToArray();
      |               ^~~~~
      |               :
a.cc:71:20: error: expected unqualified-id before '[' token
   71 |         public char[] chararr => strarr.Select(char.Parse).ToArray();
      |                    ^
a.cc:74:2: error: expected ';' after class definition
   74 | }
      |  ^
      |  ;
a.cc:80:11: error: expected ':' before 'void'
   80 |     public void wri<Type>(Type x)
      |           ^~~~~
      |           :
a.cc:80:17: error: variable or field 'wri' declared void
   80 |     public void wri<Type>(Type x)
      |                 ^~~
a.cc:80:17: error: expected ';' at end of member declaration
   80 |     public void wri<Type>(Type x)
      |                 ^~~
      |                    ;
a.cc:80:20: error: expected unqualified-id before '<' token
   80 |     public void wri<Type>(Type x)
      |                    ^
a.cc:84:2: error: expected ';' after class definition
   84 | }
      |  ^
      |  ;