#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;

int N, M, cnt[1010], m = 1e9;
string S;
int main() {
  cin >> N >> M;
  for (int i = 0; i < N; i++) {
    cin >> S;
    for (int j = 0; j < M; j++) {
      if (S[j] == 'o') cnt[j]++;
    }
  }
  for (int i = 0; i < M; i++) {
    m = min(m, cnt[i]);
  }
  cout << N - m + 1 << endl;
  return 0;
}