from collections import deque

H,W=map(int,input().split())
sx,sy,gx,gy=map(int,input().split())

MAP=[list(map(int,list(input().strip()))) for i in range(H)]
USE=[[0]*W for i in range(H)]
USE[sx-1][sy-1]=1
Q=deque([(sx-1,sy-1)])

while Q:
    x,y=Q.popleft()

    for z,w in [(x+1,y),(x-1,y),(x,y+1),(x,y-1)]:
        if 0<=z<H and 0<=w<W and USE[z][w]==0:
            if abs(MAP[x][y]-MAP[z][w])<=1:
                USE[z][w]=1
                Q.append((z,w))

    if x-2>=0:
        if USE[x-2][y]==0 and MAP[x-2][y]==MAP[x][y] and MAP[x-1][y]<MAP[x][y]:
            USE[x-2][y]=1
            Q.append((x-2,y))
    if y-2>=0:
        if USE[x][y-2]==0 and MAP[x][y-2]==MAP[x][y] and MAP[x][y-1]<MAP[x][y]:
            USE[x][y-2]=1
            Q.append((x,y-2))
    if x+2<H:
        if USE[x+2][y]==0 and MAP[x+2][y]==MAP[x][y] and MAP[x+1][y]<MAP[x][y]:
            USE[x+2][y]=1
            Q.append((x+2,y))
    if y+2<W:
        if USE[x][y+2]==0 and MAP[x][y+2]==MAP[x][y] and MAP[x][y+1]<MAP[x][y]:
            USE[x][y+2]=1
            Q.append((x,y+2))

if USE[gx-1][gy-1]==1:
    print("YES")
else:
    print("NO")