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