import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {
    public static void main(String args[] ) throws Exception {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    }

    'A' -> 'n' persons

    (p1, p2) -> p1 and p2 are related

    n  = 6

    0, 1, 2, 3, 4, 5

    0,1
    1,2
    4,5
    1,4

    (0, 1 ,2, 4, 5) , (3) => number of families = 2


    ((0), (1), (2), (3), (4), (5))
    ((0,1,2,4,5), (3) )
    return list.size();

    List<Set<Person>>
    set1 = (0,1,2) -> whether set already has the 2nd person of the pair
    set2 = (4,5)
    merge(set1,set2)
    delete set2


    Input -> Area , number of ppl, List of pairs of relations
    Ouptut -> no. of families

    Pair - int p1, p2;
    }
    public int getNumOfFamily(String area, int num, List<Pair> pairs){

        if(pair.size() == 0) return num;

        List<HashSet<Integer>> result = new ArrayList<HashSet<Integer>>();

        for(int i = 0, i< num; i++){
            HashSet<Integer> curSet = new HashSet<Integer>();
            curSet.add(i);
            result.add(curSet);
        }

        HashSet<Integer> set1, set2;

        for(Pair curPair: pairs){
            set1 = getFamily(curPair.p1, result);
            set2 = getFamily(curPair.p2, result);
            if(!set1.equals(set2)){
                set1.addAll(set2); // TODO addAll
            }
            result.remove(set2);
        }
        return result.size();
    }a

    public Set<Integer> getFamily(Person p, List<HashSet<Integer>> result){
        for(Set<Integer> curSet: result){
            if(curSet.contains(p)) return curSet;
        }
        Set<Integer> output = new Set<Integer>();
        return output;
    }

}