package xyz.smile_h.bit.algorithm.hr.gem_stones;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.*;
import java.util.stream.IntStream;

import static java.util.stream.Collectors.toList;

public class Solution {

    public static int gemstones(List<String> rocks) {
        int countInRocks = rocks.size();
        Map<String, Long> potential = new HashMap<>();
        for(String rock: rocks) {
            Map<String, Long> counter = new HashMap<>();
            Arrays.stream(rock.split("")).forEach(w -> {
                counter.put(w, counter.containsKey(w) ? counter.get(w) + 1 : 1);
            });
            counter.forEach((k, v) -> {
                if(v >= 1) {
                    potential.put(k, potential.containsKey(k) ? potential.get(k) + 1 : 1);
                }
            });
        }
        int result = 0;
        for(Long v : potential.values()){
            if(v == countInRocks) {
                result++;
            }
        }
        return result;
    }

    public static void main(String[] args) throws FileNotFoundException {
        Scanner scanner = new Scanner(new File("src/main/java/xyz/smile_h/bit/algorithm/hr/t3/case.txt"));

        int rocksCount = Integer.parseInt(scanner.nextLine().trim());

        List<String> rocks = IntStream.range(0, rocksCount).mapToObj(i -> {
                return scanner.nextLine();
        }).collect(toList());

        int result = gemstones(rocks);

        System.out.println(result);
    }
}