#include <bits/stdc++.h>
using namespace std;

#define endl '\n'
#ifdef LOCAL
    #include "debug.h"    
#else
    #define print(...)
    #define printt(...)
#endif

#define int long long

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

    vector<string>a(n);
    for( int i = 0 ; i < n ; i++ )
        cin >> a[i];
    
    vector<map<char, int>>mp1(m), mp2(m);
    vector<vector<int>>pref(n, vector<int>(m));
    vector<vector<int>>suff(n, vector<int>(m));

    for( int i = 0 ; i < m ; i++ ) {

        int mx = 0;
        for( int j = 0 ; j < n ; j++ ) {
            mp1[i][a[j][i]]++;

            mx = max(mx, mp1[i][a[j][i]]);

            pref[j][i] = mx;
        }

        mx = 0;
        for( int j = n - 1 ; j + 1 ; j-- ) {
            mp2[i][a[j][i]]++;

            mx = max(mx, mp2[i][a[j][i]]);

            suff[j][i] = mx;
        }
    }
    
    int ans = 0;
    for( int i = 0 ; i < m ; i++ ) {
        ans += suff[0][i];
    }

    for( int i = 0 ; i + 1 < n ; i++ ) {
        int temp = 0;
        for( int j = 0 ; j < m ; j++ ) {
            temp += pref[i][j] + suff[i + 1][j];
        }
        
        ans = max(ans, temp);
    }

    cout << ans << endl;
}

int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int t = 1;
    cin >> t;
    
    while( t --> 0 ) 
        run();
    
    return 0;
}