#pragma GCC optimize(2)
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef __int128_t int128;
typedef pair<int, int> pii;
#define iofast ios::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define lowbit(x) (x&(-x))
#define inv(x) qpow(x,mod-2)
#define debug(x) cout << (#x) << " = " << x << endl
#define range(x) (x).begin(), (x).end()

const int iINF = 0x3f3f3f3f;
const ll llINF = 0x3f3f3f3f3f3f3f3f;
const ll mod = 998244353;

/*---------------------------------------*/

void solve()
{
    int n;
    cin >> n;
    string s, t;
    cin >> s >> t;
    if (s == t)
        cout << 1ll * n * (n + 1) / 2 << '\n';
    else {
        vector<int>v;
        for (int i = 0;i < n;i++)
            v.push_back((s[i] - '0') ^ (t[i] - '0'));
        v.erase(unique(range(v)), v.end());
        int cnt = accumulate(range(v), 0);

        if (cnt > 2)
            cout << "0\n";
        else if (cnt == 2)
            cout << "6\n";
        else {
            v.clear();
            for (int i = 0;i < n;i++)
                v.push_back((s[i] - '0') ^ (t[i] - '0'));
            cnt = accumulate(range(v), 0);
            cout << 2 * (n - 1) << '\n';
        }
    }
}

/*---------------------------------------*/

int main()
{
    iofast;
    int t = 1;
    cin >> t;
    while (t--)
        solve();

    return 0;
}