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import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;

public class B_472
{

	InputStream is;
	PrintWriter out;
	int n;
	long a[];
	private boolean oj = System.getProperty("ONLINE_JUDGE") != null;

	void solve()
	{
		int n = ni();
		int m = ni();
		int arr[][] = new int[n][m];
		for (int i = 0; i < n; i++)
		{
			String s = ns();
			for (int j = 0; j < m; j++)
			{
				if (s.charAt(j) == '#')
				{
					arr[i][j] = 1;
				}
			}
		}
		tr(arr);
		boolean flag = true;
		int visited[] = new int[m];
		Arrays.fill(visited, -1);
		for (int i = 0; i < n; i++)
		{
			for (int j = 0; j < m; j++)
			{
				if (arr[i][j] == 1)
				{
					if (visited[j] == -1)
						visited[j] = i;
					else
					{
						if (compare(arr[i], arr[visited[j]]))
						{

						} else
						{
							flag = false;
						}
					}
				}
			}
		}
		if (flag)
		{
			out.println("Yes");
		} else
		{
			out.println("No");
		}
	}

	boolean compare(int a1[], int a2[])
	{
		tr("hi");
		tr(a1, a2);
		boolean flag = true;
		for (int i = 0; i < a1.length; i++)
		{
			if (a1[i] != a2[i])
				flag = false;
		}
		return flag;
	}

	void run() throws Exception
	{
		String INPUT = "C:\\Users\\Admin\\Desktop\\input.txt";
		is = oj ? System.in : new FileInputStream(INPUT);
		out = new PrintWriter(System.out);

		long s = System.currentTimeMillis();
		solve();
		out.flush();
		tr(System.currentTimeMillis() - s + "ms");
	}

	public static void main(String[] args) throws Exception
	{
		new Thread(null, new Runnable()
		{
			public void run()
			{
				try
				{
					new B_472().run();
				} catch (Exception e)
				{
					e.printStackTrace();
				}
			}
		}, "1", 1 << 26).start();
	}

	private byte[] inbuf = new byte[1024];
	public int lenbuf = 0, ptrbuf = 0;

	private int readByte()
	{
		if (lenbuf == -1)
			throw new InputMismatchException();
		if (ptrbuf >= lenbuf)
		{
			ptrbuf = 0;
			try
			{
				lenbuf = is.read(inbuf);
			} catch (IOException e)
			{
				throw new InputMismatchException();
			}
			if (lenbuf <= 0)
				return -1;
		}
		return inbuf[ptrbuf++];
	}

	private boolean isSpaceChar(int c)
	{
		return !(c >= 33 && c <= 126);
	}

	private int skip()
	{
		int b;
		while ((b = readByte()) != -1 && isSpaceChar(b))
			;
		return b;
	}

	private double nd()
	{
		return Double.parseDouble(ns());
	}

	private char nc()
	{
		return (char) skip();
	}

	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while (!(isSpaceChar(b)))
		{ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}

	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while (p < n && !(isSpaceChar(b)))
		{
			buf[p++] = (char) b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}

	private char[][] nm(int n, int m)
	{
		char[][] map = new char[n][];
		for (int i = 0; i < n; i++)
			map[i] = ns(m);
		return map;
	}

	private int[] na(int n)
	{
		int[] a = new int[n];
		for (int i = 0; i < n; i++)
			a[i] = ni();
		return a;
	}

	private int ni()
	{
		int num = 0, b;
		boolean minus = false;
		while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
			;
		if (b == '-')
		{
			minus = true;
			b = readByte();
		}

		while (true)
		{
			if (b >= '0' && b <= '9')
			{
				num = num * 10 + (b - '0');
			} else
			{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}

	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
			;
		if (b == '-')
		{
			minus = true;
			b = readByte();
		}

		while (true)
		{
			if (b >= '0' && b <= '9')
			{
				num = num * 10 + (b - '0');
			} else
			{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}

	private void tr(Object... o)
	{
		if (!oj)
			System.out.println(Arrays.deepToString(o));
	}

}
