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import java.awt.List;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.InputMismatchException;
import java.util.Locale;
import java.util.TimeZone;

public class B {

	public static void main(String[] args) {
		Locale.setDefault(Locale.US);
		InputStream inputstream = System.in;
		OutputStream outputstream = System.out;
		FastReader in = new FastReader(inputstream);
		PrintWriter out = new PrintWriter(outputstream);
		TaskA solver = new TaskA();
		// int testcase = in.ni();
		for (int i = 0; i < 1; i++)
			solver.solve(i, in, out);
		out.close();

	}

}

class TaskA {

	public void solve(int testnumber, FastReader in, PrintWriter out) {
		int n = in.ni();
		int m = in.ni();
		char arr[][] = new char[n][m];
		for (int i = 0; i < n; i++) {
			arr[i] = in.ns().toCharArray();
		}
		for (int i = 0 ; i < n ; ++i)
		{
			for (int j = 0 ; j < m ; ++j)
			{
				if (arr[i][j] == '#')
				{
					for (int k = i ; k < n ; ++k)
					{
						if (arr[k][j] == '#')
						{
							if (!arr[k].toString().equals(arr[i].toString()))
							{
								System.out.println("No");
								return;
							}
							
						}
					}
				}
			}
		}
		System.out.println("Yes");

	}
}

class FastReader {
	public InputStream stream;
	private byte[] buf = new byte[1024];
	private int curChar;
	private int numChars;
	private SpaceCharFilter filter;

	public FastReader(InputStream stream) {
		this.stream = stream;
	}

	public FastReader() {

	}

	public int read() {
		if (numChars == -1) {
			throw new InputMismatchException();
		}
		if (curChar >= numChars) {
			curChar = 0;
			try {
				numChars = stream.read(buf);
			} catch (IOException e) {
				throw new InputMismatchException();
			}
			if (numChars <= 0) {
				return -1;
			}
		}
		return buf[curChar++];
	}

	public int ni() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-') {
			sgn = -1;
			c = read();
		}
		int res = 0;
		do {
			if (c < '0' || c > '9') {
				throw new InputMismatchException();
			}
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(c));
		return res * sgn;
	}

	public String ns() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do {
			res.appendCodePoint(c);
			c = read();
		} while (!isSpaceChar(c));
		return res.toString();
	}

	public boolean isSpaceChar(int c) {
		if (filter != null) {
			return filter.isSpaceChar(c);
		}
		return isWhitespace(c);
	}

	public static boolean isWhitespace(int c) {
		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	}

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

	public String next() {
		return ns();
	}

	public interface SpaceCharFilter {
		public boolean isSpaceChar(int ch);
	}

}