using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

​

​

/**/

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namespace Solution

{

    public class Solution

    {

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        public static Dictionary<string, int> AverageAgeForEachCompany(List<Employee> employees)

        {

            return employees.

            GroupBy(e => e.Company).

            OrderBy(e => e.Key).

            Select(grp => new 

                        {CompanyName = grp.Key, 

                        Average = (int)Math.Round(grp.Average(e => e.Age))

                        }).

            ToDictionary(item => item.CompanyName.ToString(), item=> item.Average);

        }

        public static Dictionary<string, int> CountOfEmployeesForEachCompany(List<Employee> employees)

        {

            return employees.

            GroupBy(e => e.Company).

            OrderBy(e => e.Key).

            Select(grp => new 

                        {CompanyName = grp.Key, 

                        Count = (int)grp.Count()

                        }).

            ToDictionary(item => item.CompanyName.ToString(), item => item.Count);

        }

        public static Dictionary<string, Employee> OldestAgeForEachCompany(List<Employee> employees)

        {

            return employees.

            GroupBy(e => e.Company).

            OrderBy(e => e.Key).

            Select(grp => new 

                        {CompanyName = grp.Key, 

                         Emp = employees.Where(p => p.Company == grp.Key && p.Age == (int)grp.Max(e => e.Age)).FirstOrDefault()

                        }).ToDictionary(item => item.CompanyName.ToString(), item => item.Emp);            

        }

return employees.

​

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GroupBy(e => e.Company).

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OrderBy(e => e.Key).

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Select(grp => new 

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{CompanyName = grp.Key, 

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Count = (int)grp.Count()

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}).

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ToDictionary(item => item.CompanyName.ToString(), item => item.Count);

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}

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public static Dictionary<string, Employee> OldestAgeForEachCompany(List<Employee> employees)

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{

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return employees.

​

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GroupBy(e => e.Company).

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OrderBy(e => e.Key).

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Select(grp => new 

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{CompanyName = grp.Key, 

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Emp = employees

​

​

        public static void Main()

        {   

            int countOfEmployees = int.Parse(Console.ReadLine());

            var employees = new List<Employee>();

            for (int i = 0; i < countOfEmployees; i++)

            {

                string str = Console.ReadLine();

                string[] strArr = str.Split(' ');

                employees.Add(new Employee { 

                    FirstName = strArr[0], 

                    LastName = strArr[1], 

                    Company = strArr[2], 

                    Age = int.Parse(strArr[3]) 

                    });

            }

            foreach (var emp in AverageAgeForEachCompany(employees))

            {

                Console.WriteLine($"The average age for company {emp.Key} is {emp.Value}");

            }

            foreach (var emp in CountOfEmployeesForEachCompany(employees))

            {

                Console.WriteLine($"The count of employees for company {emp.Key} is {emp.Value}");

            }

            foreach (var emp in OldestAgeForEachCompany(employees))

            {

                Console.WriteLine($"The oldest employee of company {emp.Key} is {emp.Value.FirstName} {emp.Value.LastName} having age {emp.Value.Age}");

            }

        }

    }

    public class Employee

    {

        public string FirstName { get; set; }

        public string LastName { get; set; }

        public int Age { get; set; }

        public string Company { get; set; }

    }

}