/* {{{ Shinobu kawaii */
/*
  ______   __        _                  __                 
.' ____ \ [  |      (_)                [  |                
| (___ \_| | |--.   __   _ .--.   .--.  | |.--.   __   _   
 _.____`.  | .-. | [  | [ `.-. |/ .'`\ \| '/'`\ \[  | | |  
| \____) | | | | |  | |  | | | || \__. ||  \__/ | | \_/ |, 
 \______.'[___]|__][___][___||__]'.__.'[__;.__.'  '.__.'_/ 

*/
/* }}} */

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

// #define int long long
//struct Fast {Fast(){std::cin.tie(0);ios::sync_with_stdio(false);}} fast;

/* cpp template {{{ */

/* short */
#define pb push_back
#define mp make_pair
#define Fi first
#define Se second
#define ALL(v) (v).begin(), (v).end()
#define X real()
#define Y imag()

/* REPmacro */
#define REPS(i, a, n) for (int i = (a); i < (n); ++i)
#define REP(i, n) REPS(i, 0, n)
#define RREP(i, n) REPS(i, 1, n + 1)
#define DEPS(i, a, n) for (int i = (a); i >= n; --i)
#define DEP(i, n) DEPS(i, n, 0)

/* debug */
#define debug(x) cerr << x << " " << "(L:" << __LINE__ << ")" << '\n';

/* typedef */
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef vector<vii> viii;
typedef pair<int, int> pii;
typedef double D;
typedef complex<D> P;

/* const */
const int INF = 1001001001;
const ll LINF = 1001001001001001001ll;
const int MOD = 1e9 + 7;
const D EPS = 1e-9;
const int dx[] = {0, 1, 0, -1, 1, -1, 1, -1}, dy[] = {1, 0, -1, 0, 1, -1, -1, 1};

/* func */
inline bool inside(int y, int x, int H, int W) {return y >= 0 && x >= 0 && y < H && x < W;}
inline int in() {int x; std::cin >> x; return x;}
template <typename T> void print(T x) {std::cout << x << '\n';}
template <typename T>
void print(std::vector<T>& v, std::string s = " ") {
  REP(i, v.size()) {
    if (i != 0) std::cout << s;
    std::cout << v[i];
  }
  std::cout << '\n';
}

/* }}} */

int h, w;
int sx, sy, gx, gy;
int field[55][55];
bool vis[55][55];

const int ddx[] = {2, 0, -2, 0}, ddy[] = {0, -2, 0, 2};

void dfs(int y = sx, int x = sy)
{
  vis[y][x] = true;
  if (y == gx && x == gy) {
    return;
  }

  REP(i, 4) {
    int ny = dy[i] + y, nx = dx[i] + x;
    if (vis[ny][nx]) continue;
    if (!inside(ny, nx, h, w)) continue;
    if (abs(field[ny][nx] - field[y][x]) == 1) {
      debug("po");
      dfs(ny, nx);
    }
    if (field[ny][nx] == field[y][x]) {
      debug("po");
      dfs(ny, nx);
    }
  }

  REP(i, 4) {
    int ny = ddy[i] + y, nx = ddx[i] + x;
    if (vis[ny][nx]) continue;
    if (!inside(ny, nx, h, w)) continue;
    if (field[ny][nx] != field[y][x]) continue;
    debug("po");
    dfs(ny, nx);
  }
}

signed main()
{
  scanf("%d%d", &h, &w);
  scanf("%d%d%d%d", &sx, &sy, &gx, &gy);
  sx--; sy--; gx--; gy--;
  REP(i, h) REP(j, w) scanf("%1d", &field[i][j]);
  dfs();
  print(vis[gx][gy] ? "YES" : "NO");

  return 0;
}