Gemstones

John has collected various rocks. Each rock has various minerals embeded in it. Each type of mineral is designated by a lowercase letter in the range . There may be multiple occurrences of a mineral in a rock. A mineral is called a gemstone if it occurs at least once in each of the rocks in John’s collection.

Given a list of minerals embedded in each of John’s rocks, display the number of types of gemstones he has in his collection.

Input Format

The first line consists of an integer , the number of rocks.
Each of the next  lines contains a string where each letter represents an occurence of a mineral in the current rock.

Constraints

 length of each composition 
Each composition consists of only lower-case Latin letters (‘a’-‘z’).

Output Format

Print the number of types of gemstones in John’s collection. If there are none, print .

Sample Input

3
abcdde
baccd
eeabg

Sample Output

2

Explanation

Only  and  are gemstones. They are the only types that occur in every rock.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution {

    static int gemstone(string[] arr, int n)
        {
            HashSet<char> d = new HashSet<char>(arr[0]);
            for (int i = 1; i < arr.Length; i++)
            {
                var group = d.Intersect(arr[i]);
                d = new HashSet<char>(group.ToArray());
            }

            return d.Count();
        }

    static void Main(String[] args) {
       
            int n = Convert.ToInt32(Console.ReadLine());

            if (n < 1 && n > 100)
                Console.WriteLine(0);

            string[] arr = new string[n];
            for (int arr_i = 0; arr_i < n; arr_i++)
            {
                arr[arr_i] = Console.ReadLine();
            }
            int result = gemstone(arr, n);
            Console.WriteLine(result);
    }
}