using System;
using System.Text.RegularExpressions;
 
 
public class Test
{
	public static void Main()
	{
	    string correct = "VIEW start page";
	    string incorrect = "VIEW something else";
	    string error = "something else";
 
	    checkInput(correct);
	    checkInput(incorrect);
	    checkInput(error);
	}
 
	static void checkInput(string input) {
		Console.Write("Testing '{0}'...\n",input);
		Match match = Regex.Match(input, @"^VIEW\s+(?:(start\s+page|end)|(.*))$");
 
        if (match.Success) {
            if ( match.Groups[1].Success)
                Console.Write("Success!\n");    
            if ( match.Groups[2].Success)
                Console.Write("Expected start page or end after VIEW\n");
    	} else {
        	Console.Write("usage: VIEW [start page|end]\n");
    	}
	}
}

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