/* Problem URL: https://codeforces.com/problemset/problem/1985/H1 */

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;

#define V vector

#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)

#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)

#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;

using ll = long long;

using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;

template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
    os << vec[0];
    for (size_t i = 1; i < vec.size(); i++) {
        os << ' ' << vec[i];
    }
    os << '\n';
    return os;
}

template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
    for (auto &i : vec) {
        is >> i;
    }
    return is;
}

template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
    for (auto &i : vec) {
        os << i[0];
        for (size_t j = 1; j < i.size(); j++) {
            os << ' ' << i[j];
        }
        os << '\n';
    }
    return os;
}

template<class v>
auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
    for (auto &i : vec) {
        for (auto &j : i) {
            is >> j;
        }
    }
    return is;
}

const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;


void pre()
{

}

#define TEST 1

void solve()
{
    int n, m;
    cin >> n >> m;

    V<string> a(n);
    cin >> a;

    vi dsu(n * m);
    vi size(n * m);
    rep(i, n * m) {
        dsu[i] = i;
        size[i] = 1;
    }

    stack<pair<int, int>> s;
    auto save = [&]() {
        s.emplace(-1, -1);
    };

    auto roll = [&]() {
        while (s.top().first != -1) {
            auto [i, j] = s.top();
            size[i] -= size[j];
            dsu[j] = j;
            s.pop();
        }
    };

    function<int(int)> find_p = [&](int i) {
        if (dsu[i] == i) {
            return i;
        }
        return find_p(dsu[i]);
    };

    int ans = 1;

    auto join = [&](int i, int j) {
        i = find_p(i);
        j = find_p(j);

        if (i == j) {
            return;
        }

        if (size[i] < size[j]) {
            swap(i, j);
        }

        s.emplace(i, j);
        size[i] += size[j];
        rmax(ans, size[i]);
        dsu[j] = i;
    };

    rep(i, n) {
        rep(j, m) {
            if (a[i][j] == '.') {
                continue;
            }

            if (i > 0 && a[i - 1][j] == '#') {
                join(i * m + j, (i - 1) * m + j);
            }

            if (j > 0 && a[i][j - 1] == '#') {
                join(i * m + j, i * m + j - 1);
            }
        }
    }

    rep(i, n) {
        save();
        rep(j, m) {
            if (i > 0 && a[i - 1][j] == '#') {
                join(i * m + j, (i - 1) * m + j);
            }

            if (i < n - 1 && a[i + 1][j] == '#') {
                join(i * m + j, (i + 1) * m + j);
            }

            if (j > 0) {
                join(i * m + j, i * m + j - 1);
            }
        }
        roll();
    }

    rep(j, m) {
        save();
        rep(i, n) {
            if (i > 0) {
                join(i * m + j, (i - 1) * m + j);
            }

            if (j > 0 && a[i][j - 1] == '#') {
                join(i * m + j, i * m + j - 1);
            }
            
            if (j < m - 1 && a[i][j + 1] == '#') {
                join(i * m + j, i * m + j + 1);
            }
        }
        roll();
    }

    cout << ans << '\n';
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    pre();

    int t;
    (TEST && cin >> t) || (t = 1);
    while (t--) {
        solve();
    }
}