#define MOD_TYPE 1

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

#include <boost/multiprecision/cpp_int.hpp>
#include <boost/multiprecision/cpp_dec_float.hpp>
using Int = boost::multiprecision::cpp_int;
using lld = boost::multiprecision::cpp_dec_float_100;

/*
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
*/
using ll = long long int;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pld = pair<ld, ld>;
template <typename Q_type>
using smaller_queue = priority_queue<Q_type, vector<Q_type>, greater<Q_type>>;

constexpr ll MOD = (MOD_TYPE == 1 ? (ll)(1e9 + 7) : 998244353);
//constexpr ll MOD = 1;
constexpr int INF = (int)1e9 + 10;
constexpr ll LINF = (ll)4e18;
constexpr double PI = acos(-1.0);
constexpr double EPS = 1e-11;
constexpr int Dx[] = {0, 0, -1, 1, -1, 1, -1, 1, 0};
constexpr int Dy[] = {1, -1, 0, 0, -1, -1, 1, 1, 0};

#define REP(i, m, n) for (ll i = m; i < (ll)(n); ++i)
#define rep(i, n) REP(i, 0, n)
#define REPI(i, m, n) for (int i = m; i < (int)(n); ++i)
#define repi(i, n) REPI(i, 0, n)
#define MP make_pair
#define MT make_tuple
#define YES(n) cout << ((n) ? "YES" : "NO") << "\n"
#define Yes(n) cout << ((n) ? "Yes" : "No") << "\n"
#define possible(n) cout << ((n) ? "possible" : "impossible") << "\n"
#define Possible(n) cout << ((n) ? "Possible" : "Impossible") << "\n"
#define Yay(n) cout << ((n) ? "Yay!" : ":(") << "\n"
#define all(v) v.begin(), v.end()
#define NP(v) next_permutation(all(v))
#define dbg(x) cerr << #x << ":" << x << "\n";

inline void init_main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << setprecision(30) << setiosflags(ios::fixed);
}
template <typename T>
inline bool chmin(T &a, T b)
{
  if (a > b)
  {
    a = b;
    return true;
  }
  return false;
}
template <typename T>
inline bool chmax(T &a, T b)
{
  if (a < b)
  {
    a = b;
    return true;
  }
  return false;
}
inline ll CEIL(ll a, ll b)
{
  return (a + b - 1) / b;
}
template <typename A, size_t N, typename T>
inline void Fill(A (&array)[N], const T &val)
{
  fill((T *)array, (T *)(array + N), val);
}
template <typename T, typename U>
constexpr istream &operator>>(istream &is, pair<T, U> &p) noexcept
{
  is >> p.first >> p.second;
  return is;
}
template <typename T, typename U>
constexpr ostream &operator<<(ostream &os, pair<T, U> &p) noexcept
{
  os << p.first << " " << p.second;
  return os;
}
#pragma endregion

class UnionFind
{
public:
  vector<int> par, rank_;

  UnionFind(int n = 200010) : par(n), rank_(n, 0)
  {
    iota(begin(par), end(par), 0);
  }

  int root(int x)
  {
    return par[x] == x ? x : par[x] = root(par[x]);
  }

  bool same(int x, int y)
  {
    return root(x) == root(y);
  }

  void unite(int x, int y)
  {
    x = root(x);
    y = root(y);
    if (x == y)
      return;

    if (rank_[x] < rank_[y])
    {
      par[x] = y;
    }
    else
    {
      par[y] = x;
      if (rank_[x] == rank_[y])
        rank_[x]++;
    }
  }
};

void solve()
{
  int h, w;
  cin >> h >> w;
  int sx, sy, gx, gy;
  cin >> sx >> sy >> gx >> gy;
  sx--, sy--, gx--, gy--;
  string s[50];
  rep(i, h) cin >> s[i];
  UnionFind uf(h * w);
  rep(i, h) rep(j, w - 1)
  {
    if (abs(s[i][j] - s[i][j + 1]) <= 1)
      uf.unite(i * w + j, i * w + j + 1);
  }
  rep(i, h - 1) rep(j, w)
  {
    if (abs(s[i][j] - s[i + 1][j]) <= 1)
      uf.unite(i * w + j, (i + 1) * w + j);
  }
  rep(i, h) rep(j, w - 2)
  {
    if (s[i][j] == s[i][j + 2] and s[i][j + 1] < s[i][j])
      uf.unite(i * w + j, i * w + j + 2);
  }
  rep(i, h - 2) rep(j, w)
  {
    if (s[i][j] == s[i + 2][j] and s[i + 1][j] < s[i][j])
      uf.unite(i * w + j, (i + 2) * w + j);
  }
  YES(uf.same(sx * w + sy, gx * w + gy));
}

int main()
{
  init_main();
  solve();
}