Why

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

namespace _5.Students__LAB
{
    class Program
    {
        static void Main(string[] args)
        {
            string students = string.Empty;
            List<Student> savedStudentsInfo = new List<Student>();
            while ((students = Console.ReadLine()) != "end")
            {

                List<string> studentsInfo = students.Split().ToList();
                string firstNameOfStudent = studentsInfo[0];
                string secondNameOfStudent = studentsInfo[1];
                int ageOfStudent = int.Parse(studentsInfo[2]);
                string homeTownOfStudent = studentsInfo[3];

                Student student = new Student();
                student.firstName = firstNameOfStudent;
                student.lastName = secondNameOfStudent;
                student.age = ageOfStudent;
                student.hometown = homeTownOfStudent;

                if (IsStudentExicist(savedStudentsInfo, student.firstName, student.lastName))
                {

                    if (GetStudent(savedStudentsInfo, student.firstName ,student.lastName))
                    {

                    }
                }
                else
                {
                    savedStudentsInfo.Add(student);
                }

            }
            string inputStudents = Console.ReadLine();


            foreach (var town in savedStudentsInfo)
            {
                if (inputStudents == town.hometown)
                {
                    Console.WriteLine($"{town.firstName} {town.lastName} is {town.age} years old.");
                }
            }

        }

        static bool IsStudentExicist(List<Student> students, string firstName, string lastName)
        {
            foreach (Student student in students)
            {
                if (student.firstName == firstName && student.lastName == lastName)
                {
                    return true;
                }
            }
            return false;
        }
        static Student GetStudent(List<Student> students, string firstName, string lastName)
        {
            Student existingStudent = null;
            foreach (Student student in students)
            {
                if (student.firstName == firstName && student.lastName == lastName)
                {
                    existingStudent = student;
                }
            }
            return existingStudent;
        }
    }
    class Student
    {
        public string firstName { get; set; }
        public string lastName { get; set; }
        public int age { get; set; }
        public string hometown { get; set; }

    }
}