#include<iostream>
using namespace std;
int main(){
	//freopen("poker.in","r",stdin);
	//freopen("poker.out","w",stdout);
	int t,ans=52;
	scanf("%d",&t);
	int x['z'+1]['z'+1];
	for(int i=1;i<=t;i++){
		char y[1];
		scanf("%s",&y);
		if(x[y[0]][y[1]]==0){
			x[y[0]][y[1]]=1;
			ans--;
		}
	}
	printf("%d",ans);
	return 0;
}