from collections import deque
h,w=map(int,input().split())
sy,sx,gy,gx=map(int,input().split())
sy-=1;sx-=1;gy-=1;gx-=1
g=[list(input()) for _ in range(h)]
visit=[[False]*w for _ in range(h)]
q=deque()
q.append((sy,sx))
while q:
    y,x=q.popleft()
    if visit[y][x]:
        continue
    visit[y][x]=True
    dy=[-1,0,1,0]
    dx=[0,-1,0,1]
    for i in range(4):
        ny=y+dy[i]
        nx=x+dx[i]
        if not (0<=ny<h and 0<=nx<w):
            continue
        if abs(int(g[ny][nx])-int(g[y][x]))>1:
            continue
        if visit[ny][nx]:
            continue
        q.append((ny,nx))
    dy2=[-2,0,2,0]
    dx2=[0,-2,0,2]
    for i in range(4):
        ny2=y+dy2[i]
        nx2=x+dx2[i]
        if not (0<=ny2<h and 0<=nx2<w):
            continue
        if int(g[ny2][nx2])!=int(g[y][x]):
            continue
        if int(g[(ny2+y)//2][(nx2+x)//2])>int(g[y][x]):
            continue
        q.append((ny2,nx2))
print('YES' if visit[gy][gx] else 'NO')