binary_search.cpp

#include <algorithm>
#include <complex>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <vector>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rrep(i, n) for (int i = (n)-1; i >= 0; i--)
using namespace std;
typedef long long int lli;
typedef pair<lli, lli> P;
lli MOD = 1000000007;
int main()
{
    int n;
    while (cin >> n) {
        set<int> s, t;
        int a;
        rep(i, n)
        {
            cin >> a;
            s.insert(a);
        }
        cin >> n;
        rep(i, n)
        {
            cin >> a;
            t.insert(a);
        }
        int ans = 0;
        for (auto l : s) {
            if (t.find(l) != t.end())
                ans++;
        }
        cout << ans << endl;
    }
}