def examine(x,y):
    if x < 0 or y < 0 or x >= width or y >= height:
        return False
    elif got[y][x] == 1:
        return False
    else:
        return True

def path(x,y):
        got[y][x] = 1
        value = targ[y][x]
        queue = []
        for a,b in ([[x+1,y],[x-1,y],[x,y+1],[x,y-1]]):
            if examine(a,b) and (targ[b][a] == value - 1 or targ[b][a] == value + 1 or targ[b][a] == value):
                queue.append([a,b])
        for c,d,e,f in ([[x+2,y,x+1,y],[x-2,y,x-1,y],[x,y+2,x,y+1],[x,y-2,x,y-1]]):
            if examine(c,d) and targ[d][c] == value and targ[f][e] < value:
                queue.append([c,d])
        return queue

height,width = (int(n) for n in input().split(' '))
iniy,inix,endy,endx = (int(n) - 1 for n in input().split(' '))
targ = []
for h in range(height):
    targ.append([int(n) for n in input()])
got = [[0 for w in range(width)] for h in range(height)]
queue = [[inix,iniy]]

while queue != []:
    #print(queue)
    nextqueue = []
    for x,y in queue:
        temp = path(x,y)
        nextqueue.extend(temp)
    queue = nextqueue
if got[endy][endx] == 0:
    print("NO")
else:
    print("YES")