#include<bits/stdc++.h>
using namespace std;
int T,n;
string s,s2;
int main(){
	cin>>T;
	for(int i=0;i<T;++i){
		cin>>n>>s;
		int len=s.size(),sum=0;
		reverse(s.begin(),s.end());
		s2=s;
		reverse(s.begin(),s.end());
		for(int j=0;j<len;++j){
			if(s[j]!='A'&&s[j]!='T'&&s[j]!='C'&&s[j]!='G'&&s2[j]!='A'&&s2[j]!='T'&&s2[j]!='C'&&s2[j]!='G'){
				sum=0;
				break;
			}
			if(s[j]=='A'&&s2[j]=='T'||s[j]=='T'&&s2[j]=='A'||s[j]=='C'&&s2[j]=='G'||s[j]=='G'&&s2[j]=='C')	sum+=j+1;
		}
		cout<<sum<<endl;
	}
	return 0;
}