#define _CRT_SECURE_NO_WARNINGS
#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int,int> pii; typedef vector<pair<int,int> > vpii;
typedef long long ll; typedef vector<long long> vl; typedef pair<long long,long long> pll; typedef vector<pair<long long,long long> > vpll;
typedef vector<string> vs; typedef long double ld;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

int main() {
	int N, M;
	scanf("%d%d", &N, &M);
	vector<char*> A(N);
	rep(i, N) A[i] = new char[M+1];
	rep(i, N) scanf("%s", A[i]);
	int total = 0;
	rep(i, N) total += count(A[i], A[i] + M, '.');
	vpii ss;
	rep(i, N) rep(j, M) if(A[i][j] == '.')
		ss.push_back(mp(i, j));
	bool ans = false;
	rep(ix, 2) rep(sd, 4) {
		static const int dy[4] = {0,1,0,-1}, dx[4] = {1,0,-1,0};
		int sy = ss[ix].first, sx = ss[ix].second;
		int d = sd, y = sy, x = sx;
		vector<vector<bool> > v(N, vector<bool>(M, false));
		int cnt = 0, right = 0;
		while(1) {
			v[y][x] = true;
			++ cnt;
			int ny = -1, nx = -1, nd = -1;
			const int dds[3] = {0, 3, 1};
			rep(di, 3) {
				int dd = dds[di];
				if(dd == 1 && right >= 1) continue;
				int yy = y + dy[(d+dd)%4], xx = x + dx[(d+dd)%4];
				if(yy < 0 || yy >= N || xx < 0 || xx >= M) continue;
				if(A[yy][xx] == '#') continue;
				if(cnt == total && yy == sy && xx == sx) {
					
				}else {
					if(v[yy][xx]) continue;
				}
				ny = yy, nx = xx, nd = (d + dd) % 4;
				if(dd == 1) ++ right;
				break;
			}
			if(ny == -1) break;
			if(ny == sy && nx == sx) {
				ans = true;
				break;
			}
			y = ny, x = nx, d = nd;
		}
	}
	puts(ans ? "YES" : "NO");
	return 0;
}