#include <bits/stdc++.h>
using namespace std;
int main(){
  int N, M;
  cin >> N >> M;
  vector<string> S(N);
  for (int i = 0; i < N; i++){
    cin >> S[i];
  }
  vector<int> cnt(M, 0);
  for (int i = 0; i < N; i++){
    for (int j = 0; j < M; j++){
      if (S[i][j] == 'o'){
        cnt[j]++;
      }
    }
  }
  int mx = 0;
  for (int i = 0; i < M; i++){
    mx = max(mx, N - cnt[i]);
  }
  cout << mx + 1 << endl;
}