using System;
using System.Text.RegularExpressions;
 
public class Test
{
	public static void Main()
	{
		// somente números
		Console.WriteLine(Regex.IsMatch("0184784983324", @"^\d+$")); // True
		Console.WriteLine(Regex.IsMatch("a184784983324", @"^\d+$")); // False
 
        // somente letras
        Regex rgx = new Regex(@"^\w+$");
		Console.WriteLine(rgx.IsMatch("açãojá")); // True
 
		// não aceita letras com acento
        rgx = new Regex(@"^\w+$", RegexOptions.ECMAScript);
		Console.WriteLine(rgx.IsMatch("açãojá")); // False
	}
}

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