#include<map>
#include<string.h>
#include<iostream>
using namespace std;
map<string,string> a;
int n;
string s,ss,sss;
int ans;
int main(){
	cin>>n;
	while(n--){
		cin>>s>>ss;
		sss=s[0]+s[1];
		a[sss]=ss;
		if(a.find(ss)!=a.end()) ans++;
	}
	cout<<ans;
}