Language: C++

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Text.RegularExpressions;
using static System.Console;

namespace AtCoder_1
{
    class Program
    {
        static void Main(string[] args)
        {
            var n = CinT();

            Cout((int)Math.Ceiling(n / 2.0));


            Cin();
        }

        static Random Rand = new Random();
        static string[] AlphabetTable = new string[] { "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" };
        static int GetDigits(long num)
        {
            return (int)Math.Floor(Math.Log10(num)) + 1;
        }
        static int GetNumByDigit(long num, int digit)
        {
            return (int)((num / ((int)Math.Pow(10, digit - 1))) % 10);
        }
        static int loop(int num, int max)
        {
            if (num > max)
            {
                return num % max;
            }
            else if (num < 0)
            {
                return max - (-num) % max;
            }
            else
            {
                return num;
            }
        }
        static long GCD(long a, long b)
        {
            if (a < b) { swap(ref a, ref b); }
            if (a % b == 0) { return b; }
            else { return GCD(b, a % b); }
        }

        static long LCM(long a, long b)
        {
            return a * b / GCD(a, b);
        }

        static void swap<T>(ref T a, ref T b)
        {
            T t = a;
            a = b;
            b = t;
        }

        static readonly int MOD10_9_7 = (1000000000 + 7);
        static bool IsInt(double d) { return (int)d == d; }
        static string Cin() { return ReadLine(); }
        static string[] CinAr() { return ReadLine().Split(' '); }
        static int CinT() { return S2i(Cin()); }
        static int[] CinTAr() { return CinAr().Select((x, i) => { return S2i(x); }).ToArray(); }
        static long CinL() { return S2L(Cin()); }
        static long[] CinLAr() { return CinAr().Select((x, i) => { return S2L(x); }).ToArray(); }
        static double CinD() { return S2D(Cin()); }
        static double[] CinDAr() { return CinAr().Select((x, i) => { return S2D(x); }).ToArray(); }
        static int S2i(string s) { return int.Parse(s); }
        static long S2L(string s) { return long.Parse(s); }
        static double S2D(string s) { return double.Parse(s); }
        static void Cout(object s) { WriteLine(s); }
        static long[] yakusuu(long n)
        {
            if (n == 1) { return new long[] { 1 }; }
            List<long> res = new List<long>();
            res.Add(1);
            for (long i = 2; i <= n / 2 + 1; i++)
            {
                if (n % i == 0)
                {
                    res.Add(i);
                }
            }
            res.Add(n);
            return res.ToArray();
        }
        static bool isPrime(long num)
        {
            if (num == 1) { return false; }
            for (long i = 2; i <= Math.Sqrt(num) + 1; i++)
            {
                if (num % i == 0) { return false; }
            }
            return true;
        }

        static void CoutAr<Type>(IEnumerable<Type> types)
        {
            WriteLine(string.Join(" ", types));
        }

        public static long nCr(int n, int r)
        {
            // naive: return Factorial(n) / (Factorial(r) * Factorial(n - r));
            return nPr(n, r) / Factorial(r);
        }

        public static long nPr(int n, int r)
        {
            // naive: return Factorial(n) / Factorial(n - r);
            return FactorialDivision(n, n - r);
        }

        private static long FactorialDivision(int topFactorial, int divisorFactorial)
        {
            long result = 1;
            for (int i = topFactorial; i > divisorFactorial; i--)
                result *= i;
            return result;
        }

        private static long Factorial(int i)
        {
            if (i <= 1)
                return 1;
            return i * Factorial(i - 1);
        }
    }

    public struct Pair<T>
    {
        public T a;
        public T b;
        public T c;
        public Pair(T _a, T _b) { a = _a; b = _b; c = default(T); }
        public Pair(T _a, T _b, T _c) { a = _a; b = _b; c = _c; }
    }
}


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:6:7: error: expected nested-name-specifier before 'System'
    6 | using System.Text.RegularExpressions;
      |       ^~~~~~
a.cc:7:7: error: expected nested-name-specifier before 'static'
    7 | using static System.Console;
      |       ^~~~~~
a.cc:13:26: error: 'string' has not been declared
   13 |         static void Main(string[] args)
      |                          ^~~~~~
a.cc:13:35: error: expected ',' or '...' before 'args'
   13 |         static void Main(string[] args)
      |                                   ^~~~
a.cc:23:16: error: 'Random' does not name a type
   23 |         static Random Rand = new Random();
      |                ^~~~~~
a.cc:24:16: error: 'string' does not name a type
   24 |         static string[] AlphabetTable = new string[] { "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" };
      |                ^~~~~~
a.cc:60:21: error: variable or field 'swap' declared void
   60 |         static void swap<T>(ref T a, ref T b)
      |                     ^~~~
a.cc:60:21: error: expected ';' at end of member declaration
   60 |         static void swap<T>(ref T a, ref T b)
      |                     ^~~~
      |                         ;
a.cc:60:25: error: expected unqualified-id before '<' token
   60 |         static void swap<T>(ref T a, ref T b)
      |                         ^
a.cc:67:16: error: 'readonly' does not name a type
   67 |         static readonly int MOD10_9_7 = (1000000000 + 7);
      |                ^~~~~~~~
a.cc:69:16: error: 'string' does not name a type
   69 |         static string Cin() { return ReadLine(); }
      |                ^~~~~~
a.cc:70:16: error: 'string' does not name a type
   70 |         static string[] CinAr() { return ReadLine().Split(' '); }
      |                ^~~~~~
a.cc:72:19: error: expected unqualified-id before '[' token
   72 |         static int[] CinTAr() { return CinAr().Select((x, i) => { return S2i(x); }).ToArray(); }
      |                   ^
a.cc:74:20: error: expected unqualified-id before '[' token
   74 |         static long[] CinLAr() { return CinAr().Select((x, i) => { return S2L(x); }).ToArray(); }
      |                    ^
a.cc:76:22: error: expected unqualified-id before '[' token
   76 |         static double[] CinDAr() { return CinAr().Select((x, i) => { return S2D(x); }).ToArray(); }
      |                      ^
a.cc:77:24: error: 'string' has not been declared
   77 |         static int S2i(string s) { return int.Parse(s); }
      |                        ^~~~~~
a.cc:78:25: error: 'string' has not been declared
   78 |         static long S2L(string s) { return long.Parse(s); }
      |                         ^~~~~~
a.cc:79:27: error: 'string' has not been declared
   79 |         static double S2D(string s) { return double.Parse(s); }
      |                           ^~~~~~
a.cc:80:26: error: 'object' has not been declared
   80 |         static void Cout(object s) { WriteLine(s); }
      |                          ^~~~~~
a.cc:81:20: error: expected unqualified-id before '[' token
   81 |         static long[] yakusuu(long n)
      |                    ^
a.cc:106:21: error: variable or field 'CoutAr' declared void
  106 |         static void CoutAr<Type>(IEnumerable<Type> types)
      |                     ^~~~~~
a.cc:106:21: error: expected ';' at end of member declaration
  106 |         static void CoutAr<Type>(IEnumerable<Type> types)
      |                     ^~~~~~
      |                           ;
a.cc:106:27: error: expected unqualified-id before '<' token
  106 |         static void CoutAr<Type>(IEnumerable<Type> types)
      |                           ^
a.cc:111:15: error: expected ':' before 'static'
  111 |         public static long nCr(int n, int r)
      |               ^~~~~~~
      |               :
a.cc:117:15: error: expected ':' before 'static'
  117 |         public static long nPr(int n, int r)
      |               ^~~~~~~
      |               :
a.cc:123:16: error: expected ':' before 'static'
  123 |         private static long FactorialDivision(int topFactorial, int divisorFactorial)
      |                ^~~~~~~
      |                :
a.cc:131:16: error: expected ':' before 'static'
  131 |         private static long Factorial(int i)
      |                ^~~~~~~
      |                :
a.cc:137:6: error: expected ';' after class definition
  137 |     }
      |      ^
      |      ;
a.cc: In static member function 'static void AtCoder_1::Program::Main(int*)':
a.cc:15:13: error: 'var' was not declared in this scope
   15 |             var n = CinT();
      |             ^~~
a.cc:17:23: error: 'Math' was not declared in this scope
   17 |             Cout((int)Math.Ceiling(n / 2.0));
      |                       ^~~~
a.cc:17:36: error: 'n' was not declared in this scope
   17 |             Cout((int)Math.Ceiling(n / 2.0));
      |                                    ^
a.cc:20:13: error: 'Cin' was not declared in this scope; did you mean 'CinT'?
   20 |             Cin();
      |             ^~~
      |             CinT
a.cc: In static member function 'static int AtCoder_1::Program::GetDigits(long int)':
a.cc:27:25: error: 'Math' was not declared in this scope
   27 |             return (int)Math.Floor(Math.Log10(num)) + 1;
      |                         ^~~~
a.cc: In static member function 'static int AtCoder_1::Program::GetNumByDigit(long int, int)':
a.cc:31:39: error: 'Math' was not declared in this scope
   31 |             return (int)((num / ((int)Math.Pow(10, digit - 1))) % 10);
      |                                       ^~~~
a.cc: In static member function 'static long int AtCoder_1::Program::GCD(long int, long int)':
a.cc:50:31: error: 'ref' was not declared in this scope
   50 |             if (a < b) { swap(ref a, ref b); }
      |                               ^~~
a.cc:50:42: error: expected ')' before 'b'
   50 |             if (a < b) { swap(ref a, ref b); }
      |                                          ^
a.cc:50:30: note: to match this '('
   50 |             if (a < b) { swap(ref a, ref b); }
      |                              ^
a.cc:50:26: error: 'swap' was not declared in this scope
   50 |             if (a < b) { swap(ref a, ref b); }
      |                          ^~~~
a.cc: In static member function 'static int AtCoder_1::Program::CinT()':
a.cc:71:40: error: 'Cin' was not declared in this scope; did you mean 'CinT'?
   71 |         static int CinT() { return S2i(Cin()); }
      |                                        ^~~
      |                                        CinT
a.cc: In static member function 'static long int AtCoder_1::Program::CinL()':
a.cc:73:41: error: 'Cin' was not declared in this scope; did you mean 'CinT'?
   73 |         static long CinL() { return S2L(Cin()); }
      |                                         ^~~
      |                                         CinT
a.cc: In static member function 'static double AtCoder_1::Program::CinD()':
a.cc:75:43: error: 'Cin' was not declared in this scope; did you mean 'CinT'?
   75 |         static double CinD() { return S2D(Cin()); }
      |                                           ^~~
      |                                           CinT
a.cc: In static member function 'static int AtCoder_1::Program::S2i(int)':
a.cc:77:43: error: expected primary-expression before 'int'
   77 |         static int S2i(string s) { return int.Parse(s); }
      |                                           ^~~
a.cc:77:43: error: expected ';' before 'int'
a.cc:77:46: error: expected unqualified-id before '.' token
   77 |         static int S2i(string s) { return int.Parse(s); }
      |                                              ^
a.cc: In static member function 'static long int AtCoder_1::Program::S2L(int)':
a.cc:78:44: error: expected primary-expression before 'long'
   78 |         static long S2L(string s) { return long.Parse(s); }
      |                                            ^~~~
a.cc:78:44: error: expected ';' before 'long'
a.cc:78:48: error: expected unqualified-id before '.' token
   78 |         static long S2L(string s) { return long.Parse(s); }
      |                                                ^
a.cc: In static member function 'static double AtCoder_1::Program::S2D(int)':
a.cc:79:46: error: expected primary-expression before 'double'
   79 |         static double S2D(string s) { return double.Parse(s); }
      |                                              ^~~~~~
a.cc:79:46: error: expected ';' before 'double'
a.cc:79:52: error: expected unqualified-id before '.' token
   79 |         static double S2D(string s) { return double.Parse(s); }
      |                                                    ^
a.cc: In static member function 'static void AtCoder_1::Program::Cout(int)':
a.cc:80:38: error: 'WriteLine' was not declared in this scope
   80 |         static void Cout(object s) { WriteLine(s); }
      |                                      ^~~~~~~~~
a.cc: In static member function 'static bool AtCoder_1::Program::isPrime(long int)':
a.cc:99:35: error: 'Math' was not declared in this scope
   99 |             for (long i = 2; i <= Math.Sqrt(num) + 1; i++)
      |                                   ^~~~
a.cc: At global scope:
a.cc:139:5: error: expected unqualified-id before 'public'
  139 |     public struct Pair<T>
      |     ^~~~~~