from itertools import *
from bisect import *
#from math import *
from collections import *
from heapq import *
from random import *
from decimal import *
import numpy as np
import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
int2 = lambda x: int(x) +1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def MI1(): return map(int1, sys.stdin.readline().split())
def MI2(): return map(int2, sys.stdin.readline().split())
def MF(): return map(float, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LF(): return list(map(float, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
dij = [(1, 0), (0, 1), (-1, 0), (0, -1)]

def main():
    def dfs(i,j):
        if (i,j)==(gi,gj):return True
        h0=t[i][j]
        t[i][j]=-1
        for di,dj in dij:
            ni,nj=i+di,j+dj
            ni2,nj2=i+di*2,j+dj*2
            h1=t[ni][nj]
            if h1!=-1 and -1<=h0-h1<=1:
                if dfs(ni,nj):return True
            h2=t[ni2][nj2]
            if h2!=-1 and h2==h0 and h2>h1:
                if dfs(ni2,nj2):return True
        return False

    h,w=MI()
    si,sj,gi,gj=MI2()
    t=[[100]*(w+4) for _ in range(2)]+[[100,100]+[int(c) for c in input()]+[100,100] for _ in range(h)]+[[100]*(w+4) for _ in range(2)]
    #p2D(t)
    if dfs(si,sj):print("YES")
    else:print("NO")
    #p2D(t)

main()