#include<bits/stdc++.h>
using namespace std;
//D方片C梅花H红桃S黑桃
//123456789TJQK
struct node{
	char huase;
	char dianshu;
}a[105];
bool cmp(node a, node b){
	return a.dianshu<b.dianshu;
}
int main(){
	int n ;
	
	int sum = 1 ;//有效牌
	cin>>n;
	for(int i = 1;i<=n;i++){
		cin>>a[i].huase>>a[i].dianshu;
	}
	sort(a+1,a+n+1,cmp);
	for(int i = 2;i<=n;i++){
		if(a[i].dianshu!=a[i-1].dianshu||a[i].huase!=a[i-1].huase){
			sum++;
		}
	}
	cout<<52-sum;
	
	return 0;
}