#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;

#define fi first
#define se second
#define repl(i,a,b) for(ll i=(ll)(a);i<(ll)(b);i++)
#define rep(i,n) repl(i,0,n)
#define each(itr,v) for(auto itr:v)
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define dbg(x) cout<<#x"="<<x<<endl
#define mmax(x,y) (x>y?x:y)
#define mmin(x,y) (x<y?x:y)
#define maxch(x,y) x=mmax(x,y)
#define minch(x,y) x=mmin(x,y)
#define uni(x) x.erase(unique(all(x)),x.end())
#define exist(x,y) (find(all(x),y)!=x.end())
#define bcnt __builtin_popcount

#define INF INT_MAX/3

#define BV_SIZE 64ULL // 64bit
#define MAX_BV_NUM 100 // m <= 100*64 = 6400

unsigned long long Peq[MAX_BV_NUM][0x100];
int levenshteinDistance(string a,string b) {
  int m=a.size(),n=b.size();
  int num_of_bv = (m + BV_SIZE -1) / BV_SIZE;

  for (int i = 0; i < m; i++) {
    Peq[i / BV_SIZE][a[i]] |= 1ULL << ((unsigned long long)i % BV_SIZE);
  }

  int score = m;
  unsigned long long Pv[MAX_BV_NUM], Mv[MAX_BV_NUM], Ph[MAX_BV_NUM], Mh[MAX_BV_NUM], Xv[MAX_BV_NUM], Xh[MAX_BV_NUM], Eq[MAX_BV_NUM], Xt[MAX_BV_NUM], Xa[MAX_BV_NUM];
  unsigned long long top = 1ULL << (((unsigned long long)m - 1ULL) % BV_SIZE);

  for(int i = 0; i < num_of_bv; i++) {
    Pv[i] = ~0ULL; Mv[i] = 0ULL;
  }

  for (int j = 0; j < n; j++) {
    for(int i = 0; i < num_of_bv; i++){
      Eq[i] = Peq[i][b[j]];
      Xv[i] = Eq[i] | Mv[i];
      Xt[i] = Eq[i] & Pv[i];
    }

    unsigned long long carry = 0ULL;

    for(int i = 0; i < num_of_bv; i++){
      Xa[i] = Xt[i] + Pv[i] + carry;
      if(Xt[i] == ~0ULL && carry == 1ULL){
        carry = 1ULL;
      }else{
        unsigned long long cXt = Xt[i] + carry;
        carry = (((cXt & Pv[i]) | ((cXt | Pv[i]) & ( ~ (cXt + Pv[i]) ))) >> 63ULL) & 1ULL;
      }
    }

    for(int i = 0; i < num_of_bv; i++){
      Xh[i] = (Xa[i] ^ Pv[i]) | Eq[i];

      Ph[i] = Mv[i] | ( ~ (Xh[i] | Pv[i]) );
      Mh[i] = Pv[i] & Xh[i];
    }

    if((Ph[num_of_bv - 1] & top) != 0ULL)score++;
    else if((Mh[num_of_bv - 1] & top) != 0ULL)score--;    

    unsigned long long Ph_carry = 1ULL;
    unsigned long long Mh_carry = 0ULL;

    for(int i = 0; i < num_of_bv; i++){
      unsigned long long nxt_Ph_carry = (Ph[i] >> 63ULL) & 1ULL;
      Ph[i] = (Ph[i] << 1ULL) | Ph_carry;
      Ph_carry = nxt_Ph_carry;

      unsigned long long nxt_Mh_carry = (Mh[i] >> 63ULL) & 1ULL;
      Pv[i] = ((Mh[i] << 1ULL) | Mh_carry ) | ( ~ (Xv[i] | Ph[i]) );
      Mh_carry = nxt_Mh_carry;

      Mv[i] = Ph[i] & Xv[i];
    }

  }
  return score;
}

int main(){
	string a,b;
  cin>>a>>b;
  cout<<levenshteinDistance(a,b)<<endl;
	return 0;
}
// C - Grid Repainting 2
#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define uli unsigned long long int
#define rep(i, m, n) for (lli i = m; i < (n); i++)
#define repe(i, m, n) for (lli i = m; i <= (n); i++)
#define ALL(x) (x).begin(), (x).end()
#define SIZE(x) ((lli)(x).size())
#define MAX(x) *max_element(ALL(x))
#define MIN(x) *min_element(ALL(x))
#define _GLIBCXX_DEBUG
const lli INF = 2147483647;
const lli MINF = -2147483648;
const lli LINF = 9223372036854775807;
const lli MOD = 1000000007; //10^9+7
const double PI = acos(-1);
#define SORT(n) sort(n.begin(), n.end())
#define SORTR(n) sort(n.begin(), n.end(), greater<int>())
#define REV(n) reverse(n.begin(), n.end())
#define pb push_back
#define eb emplace_back
#define mp make_pair
#pragma GCC optimize("Ofast")
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vlli = vector<lli>;
using vvli = vector<vlli>;
using vs = vector<string>;
using vvs = vector<vs>;
using vb = vector<bool>;
using vvb = vector<vb>;
using ll = long long;
// vector入力
template <typename T>
istream &operator>>(istream &is, vector<T> &vec)
{
  for (T &x : vec)
    is >> x;
  return is;
}
// vector出力
template <typename T>
ostream &operator<<(ostream &os, vector<T> &vec)
{
  // os << '{';
  for (int i = 0; i < vec.size(); i++)
  {
    os << vec[i] << (i + 1 == vec.size() ? "" : "");
  }
  // os << '}';
  return os;
}
// aよりもbが大きいならばaをbで更新する(更新されたならばtrueを返す)
template <typename T>
bool chmax(T &a, const T &b)
{
  if (a < b)
  {
    a = b; // aをbで更新
    return true;
  }
  return false;
}
// aよりもbが小さいならばaをbで更新する(更新されたならばtrueを返す)
template <typename T>
bool chmin(T &a, const T &b)
{
  if (a > b)
  {
    a = b; // aをbで更新
    return true;
  }
  return false;
}

int main()
{
  ios::sync_with_stdio(false);
  cin.tie(0);
  lli a, b, c, h, n, w, ans = 0, count = 0;
  vector<pair<string, pair<lli, lli>>> pr;
  cin >> h >> w;
  vs s(h);
  rep(i, 0, h)
  {
    cin >> s[i];
  }
  vlli dx = {0, 1, 0, -1};
  vlli dy = {1, 0, -1, 0};
  rep(i, 0, h)
  {
    rep(j, 0, w)
    {
      if (s[i][j] == '.')
      {
        continue;
      }
      rep(k, 0, 4)
      {
        a = i + dy[k];
        b = j + dx[k];
        if (a < 0 || a >= h)
          continue;
        if (b < 0 || b >= w)
          continue;
        if (s[a][b] == '#')
          count++;
      }
      if (count == 0)
      {
        cout << "No" << endl;
        return 0;
      }
      count = 0;
    }
  }
  cout << "Yes" << endl;
}