H,W = map(int,input().split())
SG = [i-1 for i in list(map(int,input().split()))]
S = tuple(SG[:2])
G = tuple(SG[2:])
B = [[int(s) for s in input()] for _ in range(H)]
Q = {S}
dir = [[1,0],[0,1],[-1,0],[0,-1]]
nv = [[True] * W for _ in range(H)]
nv[S[0]][S[1]] = False
while Q:
    x,y = next(iter(Q))
    if G == (x,y):
        print("YES")
        exit()
    Q.remove((x,y))
    nowh = B[x][y]
    for xd,yd in dir:
        x2 = x + xd
        y2 = y + yd
        if 0 <= x2 < H and 0 <= y2 < W:
            if nv[x2][y2] and abs(B[x2][y2] - nowh) <= 1:
                nv[x2][y2] = False
                Q.add((x2,y2))
    for xd,yd in dir:
        x2 = x + xd * 2
        y2 = y + yd * 2
        x3 = x + xd
        y3 = y + yd
        if 0 <= x2 < H and 0 <= y2 < W:
            if nv[x2][y2] and B[x2][y2] == nowh and B[x3][y3] < nowh:
                nv[x2][y2] = False
                Q.add((x2,y2))

print("NO")