set - intersection uri 1104

#include <bits/stdc++.h>
using namespace std;
#define d(x) cout << #x << " = " << (x) << endl
#define fr freopen("in.txt", "r", stdin);
#define fw freopen("out.txt", "w", stdout);
#define mem(x) memset((x), 0, sizeof((x)));
#define ll long long
#define siz 100000
#define MAX 100005

int main() {
    //fr; fw;
    //////////////////////MAIN//////////////////////
    int n, m;
    while(cin >> n >> m){
        if(n == 0 && m == 0) break;
        set<int> first; //prothom set
        set<int> second; //ditio set
        //prothom set er input nitesi
        for(int i = 0; i < n; i++){
            // cin >> first[i];
            int input;
            cin >> input;
            first.insert(input);
        }
        //ditiyo set er input nitesi
        for(int i = 0; i < m; i++){
            // cin >> second[i];
            int input;
            cin >> input;
            second.insert(input);
        }
        //eta amar intersection vector, and size dite hobe duita set er size er soman.
        vector<int> v(m+n);
        //set_intersection function iterator diye kaj kore. tai ekta iterator banate hobe.
        vector<int>::iterator it;
        //then iterator e assigne kore set intersection chalalam.
        it= set_intersection (first.begin(), first.end(), second.begin(), second.end(), v.begin());
        //oita chalale size lastly (m+n) er soman thake. sekhan theke [kichu ekta kore bad diye] size thik korte hoy
        //still confused how it works though.
        v.resize(it-v.begin());

        //std::cout << "The intersection has " << (v.size()) << " elements:\n";
        //cout << first.size() << endl;
        //cout << second.size() << endl;

        if(first.size() <= second.size()) cout << (first.size()-v.size()) << endl;
        if(second.size() < first.size()) cout << (second.size()-v.size()) << endl;
    }
    return 0;