using System;
using System.Text.RegularExpressions;

class Program
{
    static void Main(string[] args)
    {
        string regex = "^[^|]*\\|[^|]*\\|[^|]*\\|\\|";

        Console.WriteLine("abc|123|234||673");
        Match myMatch = Regex.Match("abc|123|234||673", regex);
        Console.WriteLine(myMatch.Success);

        Console.WriteLine("abc|def||123|456");
        myMatch = Regex.Match("abc|def||123|456", regex);
        Console.WriteLine(myMatch.Success);

        Console.WriteLine("abc|123|234|673||ab");
        myMatch = Regex.Match("abc|123|234|673||ab", regex);
        Console.WriteLine(myMatch.Success);
        
        Console.WriteLine("abc|123|234|673||ab||");
        myMatch = Regex.Match("abc|123|234|673||ab||", regex);
        Console.WriteLine(myMatch.Success);
    }
}