Language: C++

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            while (true)
            {
                string a;
                a = Console.ReadLine();
               // Console.WriteLine(Convert.ToInt32(a));
                if (Convert.ToInt32(a) == 0) break;
                string d = "";
                string b = "";
                int c = 0;
                for (int i = 0; i <= a.Length - 1; i++)
                {
                    if (a.Substring(i, 1) != " ")
                    {
                        d = d + a.Substring(i, 1);
                        c += 1;
                    }
                    else
                    {
                        break;
                    }
                }
                for (int i = c + 1; i <= a.Length - 1; i++)
                {
                    b = b + a.Substring(i, 1);
                }
                c = int.Parse(b) + int.Parse(d);
                int z = 0;
                while (c != 0)
                {
                    c = c / 10;
                    z += 1;
                }
                Console.WriteLine(z);
            }
        }
    }
}

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:9:26: error: 'string' has not been declared
    9 |         static void Main(string[] args)
      |                          ^~~~~~
a.cc:9:35: error: expected ',' or '...' before 'args'
    9 |         static void Main(string[] args)
      |                                   ^~~~
a.cc:46:6: error: expected ';' after class definition
   46 |     }
      |      ^
      |      ;
a.cc: In static member function 'static void ConsoleApplication1::Program::Main(int*)':
a.cc:13:17: error: 'string' was not declared in this scope
   13 |                 string a;
      |                 ^~~~~~
a.cc:14:17: error: 'a' was not declared in this scope
   14 |                 a = Console.ReadLine();
      |                 ^
a.cc:14:21: error: 'Console' was not declared in this scope
   14 |                 a = Console.ReadLine();
      |                     ^~~~~~~
a.cc:16:21: error: 'Convert' was not declared in this scope
   16 |                 if (Convert.ToInt32(a) == 0) break;
      |                     ^~~~~~~
a.cc:17:24: error: expected ';' before 'd'
   17 |                 string d = "";
      |                        ^
a.cc:18:24: error: expected ';' before 'b'
   18 |                 string b = "";
      |                        ^
a.cc:24:25: error: 'd' was not declared in this scope
   24 |                         d = d + a.Substring(i, 1);
      |                         ^
a.cc:34:21: error: 'b' was not declared in this scope
   34 |                     b = b + a.Substring(i, 1);
      |                     ^
a.cc:36:21: error: expected primary-expression before 'int'
   36 |                 c = int.Parse(b) + int.Parse(d);
      |                     ^~~