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

#ifdef _RUTHEN
#include "debug.hpp"
#else
#define show(...) true
#endif

using ll = long long;
#define rep(i, n) for (int i = 0; i < (n); i++)
template <class T> using V = vector<T>;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int N, M;
    cin >> N >> M;
    V<string> S(N);
    rep(i, N) cin >> S[i];
    int ans = 0;
    rep(j, M) {
        int cur = 0;
        rep(i, N) cur += S[i][j] == 'o';
        ans = max(ans, N - cur + 1);
    }
    cout << ans << '\n';
    return 0;
}