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

namespace ConsoleApplication10
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("请输入一个整数：");
string input = Console.ReadLine();
int num;
while (true)
{
try
{
num = int.Parse(input);
for (int i = 1; i < 21; i++)
{
if (i % 2 == 1)
Console.WriteLine(i);
}
}
catch
{
Console.WriteLine("输入错误请重新输入：");
input = Console.ReadLine();
}

}
}
}
}