using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication56
{
    class Program
    {
        static void Main(string[] args)
        {
            Student student = new Student(5);
            Console.WriteLine(student.GetAge);

            Student2 student2 = new Student2();
            student2.CheckAge = 500;
            Console.WriteLine(student2.CheckAge);
        }
    }

    class Student
    {
        public Student(int age)
        {
            GetAge = age;
        }
        public int GetAge { get; private set; }
    }

    class Student2
    {
        private int _age;

        public int CheckAge
        {
            get
            { return _age; }
            set
            {
                if (_age > 0)
                    _age = value;
                else
                    return;
            }
        }
    }
}