Student Academy

using System;
using System.Collections.Generic;
using System.Linq;

namespace Student_Academy
{
    class Program
    {
        static void Main(string[] args)
        {
            int num = int.Parse(Console.ReadLine());
            var infoStudents = new Dictionary<string, List<double>>();

            for (int i = 1; i <= num; i++)
            {
                string name = Console.ReadLine();
                double grade = double.Parse(Console.ReadLine());
                if (!infoStudents.ContainsKey(name))
                {
                    infoStudents.Add(name, new List<double>());
                    infoStudents[name].Add(grade);

                }
                else
                {
                    infoStudents[name].Add(grade);
                }
            }

            foreach (var kvp in infoStudents.OrderByDescending(x=>x.Key).ThenBy(x=>x.Value.Average()))
            {

                if ((kvp.Value.Average()) >= 4.50)
                {
                    Console.WriteLine($"{kvp.Key} -> {(kvp.Value.Average()):f2}");
                }
            }
        }
    }
}