using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    static IEnumerable<string> substrings(string s, int length) {

        for (int i = 0 ; i + length <= s.Length; i++) {

            var ss = s.Substring(i, length);

            if (!(ss.StartsWith(" ") || ss.EndsWith(" ")))

                yield return ss;

        }

    }

    public static void Main()

    {

        int count = 0;

        var string1 = "images of canadian geese goslings";

        var string2 = "Canadian geese with goslings pictures to choose from, with no signup needed";

        string result = null;

        for (int i = string1.Length; i>0 && string.IsNullOrEmpty(result); i--) {

            foreach (string s in substrings(string1, i)) {

                count++;

                if (string2.IndexOf(s, StringComparison.CurrentCultureIgnoreCase) >= 0) {

                    result = s;

                    break;

                }

            }

        }

        if (string.IsNullOrEmpty(result)) 

            Console.WriteLine("no common substrings found");

        else 

            Console.WriteLine("'" + result + "'");

        Console.WriteLine(count);

    }

}