#include <bits/stdc++.h>
using namespace std;

constexpr int DX[4] = {0, -1, 0, 1}, DY[4] = {1, 0, -1, 0};
array<int, 3> G[110][110][4];

int main() {
	int N, M;
	cin >> N >> M;
	vector<string> A(N);
	for(int i = 0; i < N; ++i) cin >> A[i];
	
	auto map_check = [&](int x, int y) {
		return 0 <= x and x < N and 0 <= y and y < M and A[x][y] == '.';
	};
	
	for(int x = 0; x < N; ++x) for(int y = 0; y < M; ++y) for(int d = 0; d < 4; ++d) {
		int nx = x + DX[d], ny = y + DY[d];
		if(map_check(nx, ny)) {
			G[x][y][d] = {nx, ny, d};
			continue;
		}
		
		int nd = (d + 1) % 4;
		nx = x + DX[nd], ny = y + DY[nd];
		if(map_check(nx, ny)) {
			G[x][y][d] = {nx, ny, nd};
			continue;
		}
		
		G[x][y][d] = {-1, -1, -1};
	}
	
	int Wcnt = 0;
	for(int x = 0; x < N; ++x) for(int y = 0; y < M; ++y) if(A[x][y] == '.') Wcnt += 1;
	
	for(int sx = 0; sx < N; ++sx) for(int sy = 0; sy < M; ++sy) for(int sd = 0; sd < 4; ++sd) {
		if(G[sx][sy][sd][2] == -1) continue;
		
		int cnt = 0;
		vector seen(N, vector<bool>(M, 0));
		int x = sx, y = sy, d = sd;
		do {
			const auto v = G[x][y][d];
			x = v[0], y = v[1], d = v[2], cnt += 1;
			if(d == -1 or seen[x][y]) {
				cnt = -1;
				break;
			}
			seen[x][y] = 1;
		} while(x != sx or y != sy);
		
		if(cnt == Wcnt) {
			cout << "YES\n";
			return 0;
		}
	}
	
	cout << "NO\n";
}