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import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.Reader;
import java.math.BigInteger;
import java.util.Random;
import java.util.StringTokenizer;

public class TaskA {

    public static void main(String[] args) throws Exception {
        Tokenizer in = new Tokenizer();
        
        int n = in.nextInt(), m = in.nextInt();
        char[][] matrix = new char[n][];
        
        for(int i = 0; i < n; i++) matrix[i] = in.next().toCharArray();
        
        long[] lines = new long[n];
        for(int i = 0; i < n; i++)
            for(int j = 0; j < m; j++) 
                if(matrix[i][j] == '#') lines[i] |= 1L << j;
        
        long[] columns = new long[m];
        for(int j = 0; j < m; j++)
            for(int i = 0; i < n; i++)
                if(matrix[i][j] == '#') columns[j] |= 1L << i;
        
        boolean flag = true;
        for(int i = 0; i < n; i++)
            for(int j = i + 1; j < n; j++)
                if((lines[i] & lines[j]) != 0 && lines[i] != lines[j]) flag = false;
        
        for(int i = 0; i < m; i++)
            for(int j = i + 1; j < m; j++)
                if((columns[i] & columns[j]) != 0 && columns[i] != columns[j]) flag = false;
        
        System.out.println(flag ? "Yes" : "No");
    }

    private static class Tokenizer {

        private final BufferedReader in;
        private StringTokenizer tokenizer = null;

        public Tokenizer() throws Exception {
            this(new InputStreamReader(System.in));
        }

        public Tokenizer(Reader reader) throws Exception {
            in = new BufferedReader(reader);
        }

        public boolean hasMoreTokens() throws Exception {
            while(tokenizer == null || !tokenizer.hasMoreTokens()) {
                String line = in.readLine();
                if(line == null) return false;
                tokenizer = new StringTokenizer(line);
            }
            return true;
        }

        public String next() throws Exception {
            return hasMoreTokens() ? tokenizer.nextToken() : null;
        }

        public int nextInt() throws Exception {
            return Integer.parseInt(next());
        }

        public long nextLong() throws Exception {
            return Long.parseLong(next());
        }

    }

}
