#include<cstdio>

#include<cstring>

#include<algorithm>

#include<map>

#include<iostream>

using namespace std;

int n;

map<string,int > mp;

string a,b;

int ans;

int main()

{

    scanf("%d",&n);

    for(int i=;i<=n;i++)

    {

        cin>>a;

        int len=a.length();

        b="";

        for(int i=;i<len;i++)

        {

            if(a[i]=='A') b+='T';

            else if(a[i]=='T') b+='A';

            else if(a[i]=='C') b+='G';

            else b+='C';

        }

        if(mp[b])

        {

            ans++;

            mp[b]--;

        }

        else mp[a]++;

    }

    printf("%d",ans);

    return ;

}