from collections import deque

h,w = map(int,input().split())
sl,sr,gl,gr = map(int,input().split())
grid = [input() for i in range(h)]
ans = [[0]*w for i in range(h)]

l=[1,0,-1,0]
r=[0,1,0,-1]
ll =[2,0,-2,0]
rr=[0,2,0,-2]

d=deque()
d.append((sl-1,sr-1))

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

    for i in range(4):
        if 0 <= x+l[i] < h and 0<= y+r[i] <w:
            if abs(int(grid[x][y]) - int(grid[x+l[i]][y+r[i]])) <= 1:
                if ans[x+l[i]][y+r[i]] == 0:
                    d.append((x+l[i],y+r[i]))
                    ans[x+l[i]][y+r[i]] = 1

    for i in range(4):
        if 0 <= x+ll[i] < h and 0<= y+rr[i] <w:
            if grid[x][y] == grid[x+ll[i]][y+rr[i]] and grid[x][y] > grid[x+l[i]][y+r[i]]:
                if ans[x+ll[i]][y+rr[i]] == 0:
                    d.append((x+ll[i],y+rr[i]))
                    ans[x+ll[i]][y+rr[i]] = 1


if ans[gl-1][gr-1] == 1:
    print('YES')
else:
    print('NO')

# for i in ans:
#     print(i)