using System;

using System.Text.RegularExpressions;                   

public class Program

{

    public static void Main()

    {

        string phraze = "I'am {0} to crack {1} task {2} now.";

        var regex = new Regex(@"{\d}+");

        var matches =  regex.Matches(phraze);

        Console.WriteLine(matches.Count);

    }

}