#include <bits/stdc++.h>
using namespace std;
int main(){
	char a[206];
	int t;
	cin>>t;
	int ans;
	for(int i=1;i<2*t;i++){
		//cout<<i<<"hkjlahflkdsfhlasdkfhasldfkasjklf"<<endl;
		cin>>a[i];
		if(i%2==0){
//	cout<<"sdqahjdal;skf"<<endl;
			for(int j=i-2;j>1;j-=2){
				if(a[i]==a[j]&&a[i-1]==a[j-1]){
					//cout<<"jksfdahlaaalalalalalalalalalll"<<endl;
					//cout<<a[i]<<" "<<a[j]<<" "<<a[i-1]<<" "<<a[j-1]<<" "<<endl;
					ans++;
				}
			}
		}
	}
	//cout<<ans;
	cout<<52-t+ans<<endl;
	return 0;
}

我用样例都可以过 但不知道为什么只能得40分