#include<bits/stdc++.h>
using namespace std;
int main(){
	string a;
	int s=0,n;
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>a[i];
		if(a[0]>='A'&&a[0]<='G') s=s+1;
		else if(a[0]>='R'&&a[0]<='T') s=s+1;
}
	cout<<n-s;
	return 0;
}

/**************************************************************
	Problem: 1181
	User: huxuanchen
	Language: C++
	Result: Wrong Answer
****************************************************************/