twice counter

// ********* Assalamualaikum****** IN the name of my Almighty****:):)***
#include<bits/stdc++.h>
using namespace std;
#define suni ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define endl "\n"
#define f(i,a,b) for(int i=a;i< b;i++)
#define ff(i,a,b) for(int i= a;i>=b;i--)
#define T int t; cin >>t; while(t--)
#define vi  vector<int>
#define vll vector<long long>
#define vs vector<string>
#define vp vector<pair
#define pii pair<int,int>
#define pb push_back
#define mk make_pair
#define b(a) a.begin(),a.end()
#define rb(a) a.rbegin(),a.rend()
#define I  int
#define ll long long
#define st string
#define MN int main()
MN{
    T{
        suni;
        I n;
        cin>>n;
        map<st,I> m;
        f(i,0,n) {
            st s;
            cin>>s;
            m[s]++;
        }
        I cnt=0;
        for(auto u : m){
            if(u.second==2) cnt++;
        }
        cout<<cnt<<endl;
    }
}

//*******Happy Coding*******???******