#include<bits/stdc++.h>
using namespace std;

map<string,bool> pokes;
int main()
{
	int n;
	cin >> n;
	for(int i = 0;i < n;i++)
	{
		string str = "";
		char a,b;
		cin >> a >> b;
		str.append(1,a);
		str.append(1,b);
		pokes[str] = true;
	}
	cout << 52 - pokes.size();
	return 0;
}