Timus-1196. History Exam

#include <bits/stdc++.h>

using namespace std;
#define pb push_back
#define FastIO ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define F first
#define S second
typedef long long ll;
typedef vector< int > vi;
typedef vector< ll > V;
typedef map<int, int > mp;
#define debug cout << -1 << endl;
#define REP(i, a, b) for(int i=a; i<b; i++)
#define pop pop_back
const ll MOD = 1000000007;
const int maxN = 2001;

int dx[] = {-1, 0, 1, -1, 1, -1, 0, 1};
int dy[] = {-1, -1, -1, 0, 0, 1, 1, 1};

void solve()
{
    int n, nn;
    cin >> n;
    mp m;
    while(n--) {
        int x;
        cin >> x;
        m[x]++;
    }
    cin >> nn;
    int cnt = 0;
    while(nn--) {
        int x;
        cin >> x;
        if(m[x]) cnt++;
    }
    cout << cnt << endl;
    return;
}

int main()
{
    FastIO;
    //freopen("billboard.in","r",stdin);
    //freopen("billboard.out","w",stdout);
    int t;
    t = 1;
    //cin >> t;
    while(t--){
        solve();
    }
    return 0;
}