#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
#define rep(i,n) for(int i=0; i<(int)(n); i++)



int main(){
    int N, M; cin >> N >> M;
    vector<string> A(N);
    rep(i,N) cin >> A[i];
    vector<int> C(M,0);
    rep(i,N) rep(j,M) if(A[i][j] == 'o') C[j]++;
    int ans = 0;
    rep(i,M) ans = max(ans, N-C[i]+1);
    cout << ans << '\n';
    return 0;
}

struct ios_do_not_sync{
    ios_do_not_sync(){
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
    }
} ios_do_not_sync_instance;