#include <stdio.h>
#include <string.h>
void solve() {
    int N, M;
    scanf("%d %d", &N, &M);
    char T[N][M + 1];
    int max_score = 0;
    for (int i = 0; i < N; i++) {
        scanf("%s", T[i]);
    }
    for (int j = 0; j < M; j++) {
        int freq[26] = {0}, max_freq = 0;
        for (int i = 0; i < N; i++) {
            freq[T[i][j] - 'a']++;
            if (freq[T[i][j] - 'a'] > max_freq) {
                max_freq = freq[T[i][j] - 'a'];
            }
        }
        max_score += max_freq;
    }
    printf("%d\n", max_score);
}
int main() {
    int Tc;
    scanf("%d", &Tc);
    while (Tc--) {
        solve();
    }
    return 0;
}