import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintWriter; import java.util.Arrays; import java.util.StringTokenizer; public class Main { static BufferedReader in; static PrintWriter out; static StringTokenizer tok; void solve() throws IOException { int h = ni(); int w = ni(); String[] s = nsa(h); boolean[][] used = new boolean[h][w]; for (int i = 0; i < h; i++) { outside: for (int j = 0; j < w; j++) { if (i == 0 && j == 0) { continue; } for (int k = 0; k < h; k++) { Arrays.fill(used[k], false); } for (int k = 0; k < h; k++) { for (int l = 0; l < w; l++) { if (s[k].charAt(l) == '#' && !used[k][l]) { if (k + i > h - 1 || l + j > w - 1) { continue outside; } if (s[k + i].charAt(l + j) == '.' || used[k + i][l + j]) { continue outside; } used[k + i][l + j] = true; } } } out.println("YES"); return; } } out.println("NO"); } String ns() throws IOException { while (!tok.hasMoreTokens()) { tok = new StringTokenizer(in.readLine(), " "); } return tok.nextToken(); } int ni() throws IOException { return Integer.parseInt(ns()); } long nl() throws IOException { return Long.parseLong(ns()); } double nd() throws IOException { return Double.parseDouble(ns()); } String[] nsa(int n) throws IOException { String[] res = new String[n]; for (int i = 0; i < n; i++) { res[i] = ns(); } return res; } int[] nia(int n) throws IOException { int[] res = new int[n]; for (int i = 0; i < n; i++) { res[i] = ni(); } return res; } long[] nla(int n) throws IOException { long[] res = new long[n]; for (int i = 0; i < n; i++) { res[i] = nl(); } return res; } public static void main(String[] args) throws IOException { in = new BufferedReader(new InputStreamReader(System.in)); out = new PrintWriter(System.out); tok = new StringTokenizer(""); Main main = new Main(); main.solve(); out.close(); } }