using System;
public class Test
{
public static void Main()
{
String txt = "111\n222\n333\n444\n555\n666\n777\n888\n999\n000";
String[] arr = txt.Split("\n".ToCharArray());
for(int i = 1; i < arr.Length; i += 2)
{
Console.WriteLine(arr[i]);
Console.WriteLine(arr[i-1]);
}
if(arr.Length % 2 != 0)
Console.WriteLine(arr[arr.Length - 1]);
}
}
dXNpbmcgU3lzdGVtOwoKcHVibGljIGNsYXNzIFRlc3QKewoJcHVibGljIHN0YXRpYyB2b2lkIE1haW4oKQoJewoJCVN0cmluZyB0eHQgPSAiMTExXG4yMjJcbjMzM1xuNDQ0XG41NTVcbjY2NlxuNzc3XG44ODhcbjk5OVxuMDAwIjsKCQlTdHJpbmdbXSBhcnIgPSB0eHQuU3BsaXQoIlxuIi5Ub0NoYXJBcnJheSgpKTsKCQlmb3IoaW50IGkgPSAxOyBpIDwgYXJyLkxlbmd0aDsgaSArPSAyKQoJCXsKCQkJQ29uc29sZS5Xcml0ZUxpbmUoYXJyW2ldKTsKCQkJQ29uc29sZS5Xcml0ZUxpbmUoYXJyW2ktMV0pOwoJCX0KCQlpZihhcnIuTGVuZ3RoICUgMiAhPSAwKQoJCQlDb25zb2xlLldyaXRlTGluZShhcnJbYXJyLkxlbmd0aCAtIDFdKTsKCX0KfQ==