package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
	"strconv"
)

func out(x ...interface{}) {
	fmt.Println(x...)
}

var sc = bufio.NewScanner(os.Stdin)

func getInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func getInts(N int) []int {
	ret := make([]int, N)
	for i := 0; i < N; i++ {
		ret[i] = getInt()
	}
	return ret
}

func getString() string {
	sc.Scan()
	return sc.Text()
}

// min, max, asub, absなど基本関数
func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func asub(a, b int) int {
	if a > b {
		return a - b
	}
	return b - a
}

func abs(a int) int {
	if a >= 0 {
		return a
	}
	return -a
}

func lowerBound(a []int, x int) int {
	idx := sort.Search(len(a), func(i int) bool {
		return a[i] >= x
	})
	return idx
}

func upperBound(a []int, x int) int {
	idx := sort.Search(len(a), func(i int) bool {
		return a[i] > x
	})
	return idx
}

func main() {
	sc.Split(bufio.ScanWords)
	sc.Buffer([]byte{}, 1000000)
	N, M := getInt(), getInt()
	s := make([]string, N)
	for i := 0; i < N; i++ {
		s[i] = getString()
	}

	cnt := 0
	dx := []int{-1, 1, 0, 0}
	dy := []int{0, 0, -1, 1}
	for y := 0; y < N; y++ {
		for x := 0; x < M; x++ {
			if s[y][x] == '#' {
				cnt++
				continue
			}
			c := 0
			for i := 0; i < 4; i++ {
				xx := x + dx[i]
				yy := y + dy[i]
				if xx < 0 || xx >= M || yy < 0 || yy >= N {
					continue
				}
				if s[yy][xx] == '#' {
					continue
				}
				c++
			}
			if c <= 1 {
				out("NO")
				return
			}
		}
	}

	if N == 1 || M == 1 {
		if N*M == 2 {
			out("YES")
			return
		}
	}

	if N%2 == 1 && M%2 == 1 {
		if cnt%2 == 1 {
			out("YES")
			return
		}
		out("NO")
		return
	}

	if cnt%2 == 0 {
		out("YES")
		return
	}

	out("NO")
}