from collections import deque
import bisect
import math
from decimal import Decimal
import heapq
import sys
sys.setrecursionlimit(10**9)

h,w = map(int,input().split())
sx,sy,ex,ey = map(int,input().split())
bb = [list(input()) for i in range(h)]
b = [[1 for i in range(w+1)] for j in range(h+1)]
for i in range(h):
    for j in range(w):
        b[i+1][j+1] = int(bb[i][j])

q = deque([])
d = [[1 for i in range(w+1)] for j in range(h+1)]
d[sx][sy] = 0
q.append((sx,sy))

lis = [[1,0],[-1,0],[0,1],[0,-1]]

while q:
    (x,y) = q.popleft()
    if x == ex and y == ey:
        print("YES")
        exit()
    
    # 1masu
    for xx,yy in lis:
        if 1 <= x + xx <= h and 1 <= y + yy <= w:
            if abs(b[x+xx][y+yy] - b[x][y]) <= 1:
                if d[x+xx][y+yy] == 1:
                    d[x+xx][y+yy] = 0
                    q.append((x+xx,y+yy))
    
    # 2masu
    for xx,yy in lis:
        if 1 <= x + 2*xx <= h and 1 <= y + 2*yy <= w:
            if b[x+xx][y+yy] <= b[x][y] and b[x+2*xx][y+2*yy] == b[x][y]:
                if d[x+2*xx][y+2*yy] == 1:
                    d[x+2*xx][y+2*yy] = 0
                    q.append((x+2*xx,y+2*yy))

print("NO")