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import java.io.*;
import java.util.*;

public class MainA {
	static final StdIn in = new StdIn();
	static final PrintWriter out = new PrintWriter(System.out);
	static int n, m;
	static char[][] grid;
	static boolean[][] vis;
	
	public static void main(String[] args) {
		n=in.nextInt();
		m=in.nextInt();
		grid = new char[n][];
		for(int i=0; i<n; ++i)
			grid[i]=in.next().toCharArray();
		vis = new boolean[n][m];
		for(int i=0; i<n; ++i)
			for(int j=0; j<m; ++j) {
				if(grid[i][j]=='.'||vis[i][j])
					continue;
				List<Pair> con = new ArrayList<Pair>();
				dfs(i, j, con);
				Set<Integer> rows = new HashSet<Integer>(), cols = new HashSet<Integer>();
				for(Pair p : con) {
					rows.add(p.a);
					cols.add(p.b);
				}
				if(rows.size()*cols.size()!=con.size()) {
					System.out.println("No");
					System.exit(0);
				}
			}
		out.println("Yes");
		out.close();
	}
	
	static void dfs(int i, int j, List<Pair> con) {
		vis[i][j]=true;
		con.add(new Pair(i, j));
		for(int i2=0; i2<n; ++i2)
			if(grid[i2][j]=='#'&&!vis[i2][j])
				dfs(i2, j, con);
		for(int j2=0; j2<m; ++j2)
			if(grid[i][j2]=='#'&&!vis[i][j2])
				dfs(i, j2, con);
	}
	
	static class Pair {
		int a, b;
		Pair(int a, int b) {
			this.a=a;
			this.b=b;
		}
	}
	
	static class StdIn {
		final private int BUFFER_SIZE = 1 << 16;
		private DataInputStream din;
		private byte[] buffer;
		private int bufferPointer, bytesRead;
		public StdIn() {
			din = new DataInputStream(System.in);
			buffer = new byte[BUFFER_SIZE];
			bufferPointer = bytesRead = 0;
		}
		public StdIn(InputStream in) {
			try{
				din = new DataInputStream(in);
			} catch(Exception e) {
				throw new RuntimeException();
			}
			buffer = new byte[BUFFER_SIZE];
			bufferPointer = bytesRead = 0;
		}
		public String next() {
			int c;
			while((c=read())!=-1&&(c==' '||c=='\n'||c=='\r'));
			StringBuilder s = new StringBuilder();
			while (c != -1)
			{
				if (c == ' ' || c == '\n'||c=='\r')
					break;
				s.append((char)c);
				c=read();
			}
			return s.toString();
		}
		public String nextLine() {
			int c;
			while((c=read())!=-1&&(c==' '||c=='\n'||c=='\r'));
			StringBuilder s = new StringBuilder();
			while (c != -1)
			{
				if (c == '\n'||c=='\r')
					break;
				s.append((char)c);
				c = read();
			}
			return s.toString();
		}
		public int nextInt() {
			int ret = 0;
			byte c = read();
			while (c <= ' ')
				c = read();
			boolean neg = (c == '-');
			if (neg)
				c = read();
			do
				ret = ret * 10 + c - '0';
			while ((c = read()) >= '0' && c <= '9');

			if (neg)
				return -ret;
			return ret;
		}
		public int[] readIntArray(int n, int os) {
			int[] ar = new int[n];
			for(int i=0; i<n; ++i)
				ar[i]=nextInt()+os;
			return ar;
		}
		public long nextLong() {
			long ret = 0;
			byte c = read();
			while (c <= ' ')
				c = read();
			boolean neg = (c == '-');
			if (neg)
				c = read();
			do
				ret = ret * 10 + c - '0';
			while ((c = read()) >= '0' && c <= '9');
			if (neg)
				return -ret;
			return ret;
		}
		public long[] readLongArray(int n, long os) {
			long[] ar = new long[n];
			for(int i=0; i<n; ++i)
				ar[i]=nextLong()+os;
			return ar;
		}
		public double nextDouble() {
			double ret = 0, div = 1;
			byte c = read();
			while (c <= ' ')
				c = read();
			boolean neg = (c == '-');
			if (neg)
				c = read();
			do
				ret = ret * 10 + c - '0';
			while ((c = read()) >= '0' && c <= '9');
			if (c == '.')
				while ((c = read()) >= '0' && c <= '9')
					ret += (c - '0') / (div *= 10);
			if (neg)
				return -ret;
			return ret;
		}
		private void fillBuffer() throws IOException {
			bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
			if (bytesRead == -1)
				buffer[0] = -1;
		}
		private byte read() {
			try{
				if (bufferPointer == bytesRead)
					fillBuffer();
				return buffer[bufferPointer++];
			} catch(IOException e) {
				throw new RuntimeException();
			}
		}
		public void close() throws IOException {
			if (din == null)
				return;
			din.close();
		}
	}
}