#include <bits/stdc++.h>

using namespace std;

using int128 = __int128_t;

#define rep(i, n)         for (int i = 0; i < n; ++i)
#define reps(i, n, s)     for (int i = 0; i < n; i += s)
#define repl(i, l, r)     for (int i = l; i < r; ++i)
#define repsl(i, l, r, s) for (int i = l; i < r; i += s)

#define all(iterable) (iterable).begin(), (iterable).end()

constexpr int dx4[4] = {1, 0, -1, 0};
constexpr int dy4[4] = {0, 1, 0, -1};

constexpr int dx8[8] = {1, 1, 0, -1, -1, -1, 0, 1};
constexpr int dy8[8] = {0, 1, 1, 1, 0, -1, -1, -1};

template <typename T>
void print(const vector<T>& vec, const string sep = " ", const string end = "\n") {
    int n = vec.size();
    rep(i, n) {
        cout << vec[i];
        if (i < n - 1) cout << sep;
        else cout << end;
    }
}

template <typename T>
void read(vector<T>& a, int begin_index, int length) {
    if (a.size() < begin_index + length) a.resize(begin_index + length);
    while (length --> 0) cin >> a[begin_index++];
}
template <typename T>
void read(vector<T>& a) { read(a, 0, a.size()); }

constexpr size_t M = 500010;

int main() {
    size_t n, m;
    cin >> n >> m;
    auto in = [&](int x, int y) { return 0 <= x and x < n and 0 <= y and y < m; };
    auto out = [&](int x, int y) { return not in(x, y); };
    vector<vector<char>> g(n, vector<char>(m));
    size_t k = 0;
    for (auto& r : g) {
        read(r);
        for (char c : r) k += c == '.';
    }
    vector<vector<bool>> vis(n, vector<bool>(m, false));
    rep(i, n) rep(j, m) {
        if (g[i][j] == '#') continue;
        rep(t, 4) {
            for (auto& r : vis) r.assign(m, false);
            size_t d = t;
            int x = i, y = j;
            vis[x][y] = true;
            size_t rest = k - 1;
            while (true) {
                int nx = x + dx4[d], ny = y + dy4[d];
                if (out(nx, ny) or g[nx][ny] == '#') {
                    d = (d + 1) & 3;
                    nx = x + dx4[d], ny = y + dy4[d];
                }
                if (in(nx, ny) and g[nx][ny] == '.') {
                    x = nx, y = ny;
                    if (vis[x][y]) break;
                    vis[x][y] = true;
                    --rest;
                } else break;
            }
            if (rest == 0 and x == i and y == j) {
                cout << "YES\n";
                return 0;
            }
        }
    }
    cout << "NO\n";
    return 0;
}