#include<stdio.h>

int main()
{
	int n;
	scanf("%d",&n);
	char a[n],i;
	for(i=0;i<n;i++){
		scanf("%s",&a[i]);
	}
	int s=0;
		for(i=0;i<n;i++){
			if(a[0]>='A'&&a[0]<='G'||a[0]>='R'&&a[0]<='T'){
				s++;
		}
		break;
				}
				printf("%d",n-s);
	
	



return 0;
}

/**************************************************************
	Problem: 1181
	User: admin
	Language: C
	Result: Accepted
	Time:9 ms
	Memory:1144 kb
****************************************************************/