#include <bits/stdc++.h>

#define rep(i, l, r) for(int i = (int)l; i < (int)r; i++)
#define all(v) v.begin(), v.end()
#define sz(v) (int)v.size()
using namespace std;

using ll = long long;
using pll = pair<ll, ll>;
using pii = pair<int, int>;
using ld = long double;

typedef vector<ll> vl;
typedef vector<int> vi;

template<class T>
void out(const vector<T> &v) {
    for (auto x: v)cout << x << " ";
    cout << endl;
}
vector<int> f = {1, 0, 0, 0, 1, 0, 1, 0, 2, 1};

void solve() {
    
    int n;cin >> n;
    string s, t;cin >> s >> t;
    
    int cnt = 0, l = -1;
    for (int i = 0, j; i < n; i = j) {
        j = i;
        while (j < n && (s[i] == t[i]) == (s[j] == t[j])) j++;
        if (s[i] != t[i]) {
            cnt++;
            // cout << j << " " << i << endl;
            l = j - i;
        }
    }
    // cout << cnt << " " << l << endl;

    if (cnt == 0) {
        ll x = n;
        cout << x * (x + 1)/ 2 << endl;
    }
    else if (cnt == 1) {
        cout << 2 * (l - 1) << endl;
    }
    else if (cnt == 2) {
        cout << 6 << endl;
    }
    else {
        cout << 0 << endl;
    }

}

int main() {


    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int T; cin >> T;
    while(T--) {
        solve();
    }
    
}