#include <bits/stdc++.h> #define rep(i, n) for (int i = 0; i < (n); i++) using namespace std; using pii = pair<int, int>; using ll = long long; int main() { int n, m; cin >> n >> m; vector<string> s(n); rep(i, n) cin >> s[i]; vector<int> cnt(m); rep(i, n) { rep(j, m) { if (s[i][j] == 'x') cnt[j]++; } } sort(cnt.rbegin(), cnt.rend()); int ans = cnt[0] + 1; cout << ans << endl; return 0; }