#pragma GCC optimize("Ofast")

//booster_^^
#include<bits/stdc++.h>

#define FC(a,b,c) for(int i=a;i<b;i++)cin>>c[i]
#define Fn(n) for(int i=0;i<n;i++)
#define fin(a,n) for(int i=0;i<n;i++)cin>>a[i]
#define F(a,b) for(int i=a;i<b;i++)
#define all(a) a.begin(),a.end()
#define umap_boost(x) x.reserve(1024);x.max_load_factor(0.25);

#define PII pair<int,int> 
#define ll long long
#define endl '\n'
using namespace std;

inline void cin_unlocked()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
}

template <typename T>
inline void stable_unique(vector<T>& v ){
    set<T> m(v.begin(),v.end());
    v.assign(m.begin(),m.end());
}


class dsu{
public:
    int n;
    vector<int> c;

    int q(int x){
        if(c[x]!=x){
            c[x]=q(c[x]);
        }
        return c[x];
    }
    void u(int a,int b){
        int fa=q(a);
        int fb=q(b);
        if(fa!=fb)
            c[fa]=fb;
    }

    dsu(int &_n){
        this->n=_n+5;
        this->c.resize(n);
        for(int i=0;i<n;i++)c[i]=i;
    }

};

int pow_mod(int a, int b,int mod) {//a^b
    int ans = 1;
    while(b > 0) {
        if(b & 1) ans = ans * a % mod; 
        a = a * a % mod;
        b >>= 1;
    }
    return ans;
}

inline void solve(){
	int n;
	cin>>n;
	string s,t;
	cin>>s>>t;
	string d=s;
	vector<int> dif[3]; 

	if(n==1){
		cout<<(s[0]==t[0])<<endl;
		return;
	}
	int l=1;
	for(int i=0;i<n;i++){
		d[i]=s[i]==t[i];
		if(!i)continue;
		if(d[i]!=d[i-1]){
			dif[!d[i]].emplace_back(l);
			l=1;
		}else{
			l++;
		}
	}

	if(l){
		dif[d[n-1]].emplace_back(l);
	}

	if(dif[1].size()==0){
		cout<<n+(n*(n-1))/2<<endl;
	}else if(dif[1].size() == 1){
		cout<<2*(n-1)<<endl;
	}else if (dif[1].size() == 2){
		cout<<6<<endl;
	}else{
		cout<<0<<endl;
	}

}

int main(){
	cin_unlocked();
	int t;cin>>t;for(;t--;)
	   solve();

	return 0;
}