#include <bits/stdc++.h>

using namespace std;
using ll = long long;
const ll mod = 1e9 + 7;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    ll testcases;
    cin >> testcases;
    while (testcases--) {

        ll n, m;
        cin >> n >> m;
        vector < string > arr;
        for (ll i = 0; i < n; i++) {
            string s;
            cin >> s;
            arr.push_back(s);
        }
        string t;
        for (ll i = 0; i < m; i++) t.push_back('A');
        arr.push_back(t);

        ll pre[n + 1][m][26];
        memset(pre, 0, sizeof(pre));
        for (ll i = 0; i < n; i++) {
            for (ll j = 0; j < m; j++) {
                for (ll k = 0; k < 26; k++) {
                    if (arr[i][j] - 'a' == k) pre[i][j][k] = 1;
                }
            }
            if (i) {
                for (ll j = 0; j < m; j++) {
                    for (ll k = 0; k < 26; k++) {
                        pre[i][j][k] += pre[i - 1][j][k];
                    }
                }
            }
        }
        ll suff[n + 1][m][26];
        memset(suff , 0, sizeof(suff));
        for (ll i = n - 1 ; i >= 0 ; i--) {
            for (ll j = 0 ; j < m ; j++) {
                for (ll k = 0 ; k < 26 ; k++) {
                    if (arr[i][j] - 'a' == k) suff[i][j][k] = 1;
                    suff[i][j][k] += suff[i + 1][j][k];
                }
            }
        }
        
        
        ll ans = 0;
        for(ll i = 0 ; i < n ; i++){
            ll total = 0;
            for(ll j = 0 ; j < m ; j++){
                ll curr = 0 , op = 0;
                for(ll k = 0 ; k < 26 ; k++) op = max(op , suff[i + 1][j][k]);
                for(ll k = 0 ; k < 26 ; k++) curr = max(curr , op + pre[i][j][k]);
                total += curr;
            }
            ans = max(ans , total);
        }
        
        cout << ans << "\n";
        
    }
    return 0;
}
// Author : Raj (raj_singh35)