#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>
using namespace std;

int ones(int x) {
    int count = 0;
    while (x > 0) {
        count += (x % 2);
        x >>= 1;
    }
    return count;
}

int main() {
    int N, K;
    cin >> N >> K;

    vector <int> subs(N);
    for (int i = 0; i < N; i++) {
        string s;
        cin >> s;
        int sub = 0;
        for (char c : s) {
            sub = (sub << 1) | (c == 'T');
        }
        subs[i] = sub;
    }

    int best_lowest = 0;
    for (int ans = 0; ans < pow(2, K); ans++) {
        int lowest = pow(2, K);
        for (int sub : subs) {
            lowest = min(lowest, ones(sub ^ ans));
        }
        best_lowest = max(best_lowest, lowest);
    }
    cout << best_lowest << endl;
    return 0;
}