using System;

using System.Collections.Generic;

public class Program {

  public static bool IsPrime(int value) {

    if (value <= 1)    

      return false;

    if (value % 2 == 0)  

      return value == 2;

    for (int divisor = 3; ; divisor += 2) {

        var (q, r) = int.DivRem(value, divisor);

        if (r == 0)

            return false;

        if (q < divisor)

            return true;

    }

  }    

  public static IEnumerable<int> AllPrimesInRange(int lowerEdge, int upperEdge) {

    lowerEdge = Math.Max(lowerEdge, 2);

​

    // Special Case - 2 - the only even prime

    if (lowerEdge == 2 && upperEdge >= lowerEdge)

      yield return 2; 

    lowerEdge = (lowerEdge / 2 * 2 + 1);  

​

    for (int number = lowerEdge; number <= upperEdge; number += 2) 

      if (IsPrime(number))

        yield return number;

  } 

  public static void Main() {

    foreach (int number in AllPrimesInRange(28, 165))

        Console.WriteLine(number);

  }

}