жаккар

using System;
using System.Text;
using System.Collections.Generic;
using System.Text.RegularExpressions;

class MainClass
{
  static int Minimum(int a, int b, int c)
 {
   int min = 0;

   if (a <= b && a <= c)
    min = a;
   else if (b <= a && b <= c)
    min = b;
   else if (c <= a && c <= b)
    min = c;
   return min;
 }

  public static string Replace_s(string str)
  {
    Regex regF = new Regex(@"[^a-z0-9\s]");
            str = regF.Replace(str.ToLower(), string.Empty);

            MatchCollection regS = Regex.Matches(str, @"[a-z0-9]{4,}\s?");

            str = "";
            foreach (Match match in regS)
            {
              str += match.Value;
            }

            return str;
  }

  public static void Jaccard(string firstString, string secondString)
  {
   double c = 0.0;
   double length = 0.0;
   double n = firstString.Length;
   double m = secondString.Length;

   if (n <= m)
    length = n;
     else length = m;

   for (int i = 0; i < length; i++)
     if (firstString[i] == secondString[i])
      c++;

   //Console.WriteLine("{0} {1} {2}", n, m, c);
   double result = c/(n+m-c);
   Console.Write(Math.Round(result, 8));
  }

  public static void Main(string[] args)
  {
    string firstString;
    string secondString;

    firstString = Console.ReadLine();
    secondString = Console.ReadLine();
     firstString = Replace_s(firstString);
     secondString = Replace_s(secondString);

    Jaccard(firstString, secondString);
}
}