rt

#include<bits/stdc++.h>
using namespace std;
bool bsy(char x){
	if(x=='A'||x=='T'||x=='C'||x=='G')
		return false;
	return true;
}
bool work(char x,char y){
	if(x=='A'&&y=='T')
		return true;
	if(x=='T'&&y=='A')
		return true;
	if(x=='C'&&y=='G')
		return true;
	if(x=='G'&&y=='C')
		return true;
	return false;
}
int t,n;
char s[100002];
int main(){
	scanf("%d",&t);
	while(t--){
		bool b=false;
		scanf("%d%s",&n,s+1);
		for(int i=1;i<=n;i++)
			if(bsy(s[i])){
				b=true;
				printf("0\n");
				break;
			}
		if(b)
			continue;
		int ans=0;
		for(int i=1;i<=n/2;i++)
			if(work(s[i],s[n-i+1]))
				ans+=n+1;
		printf("%d\n",ans);
	}
}