#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int maxn=1000000;
ll T,n;
string str1,str2;
int a[maxn+50];

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cin >> T;
	for (;T--;){
		cin >> n;
		cin >> str1;
		cin >> str2;
		for (int i=1;i<=n;i++) a[i]=(str1[i-1]!=str2[i-1]);
		a[n+1]=0;
		ll cnt=0;
		for (int i=1;i<=n+1;i++) if (a[i]!=a[i-1]) cnt++;
		/*
		cout << "------------------" << endl;
		for (int i=1;i<=n+1;i++) cout << a[i] << " ";
		cout << endl;
		cout << "cnt : " << cnt << endl;
		*/
		ll ans=0;
		if (cnt==0) ans=(n+1)*n/2;
		else if (cnt==2) ans=2*(n-1);
		else if (cnt==4) ans=6;
		cout << ans << "\n";
	}
	return 0;
}