class UnionFind:
    def __init__(self, n):
        self.par = [-1]*n
        self.rank = [0]*n

    def Find(self, x):
        if self.par[x] < 0:
            return x
        else:
            self.par[x] = self.Find(self.par[x])
            return self.par[x]

    def Unite(self, x, y):
        x = self.Find(x)
        y = self.Find(y)

        if x != y:
            if self.rank[x] < self.rank[y]:
                self.par[y] += self.par[x]
                self.par[x] = y
            else:
                self.par[x] += self.par[y]
                self.par[y] = x
                if self.rank[x] == self.rank[y]:
                    self.rank[x] += 1

    def Same(self, x, y):
        return self.Find(x) == self.Find(y)

    def Size(self, x):
        return -self.par[self.Find(x)]

h, w = map(int, input().split())
sx, sy, gx, gy = map(int, input().split())
sx, sy = sx-1, sy-1
gx, gy = gx-1, gy-1
B = []
for i in range(h):
    b = list(str(input()))
    b = [int(i) for i in b]
    B.append(b)

uf = UnionFind(h*w)
for x in range(h):
    for y in range(w):
        v = x*w+y
        for dx, dy in (-1, 0), (1, 0), (0, -1), (0, 1):
            nx, ny = x+dx, y+dy
            if 0 <= nx < h and 0 <= ny < w:
                if abs(B[x][y]-B[nx][ny]) <= 1:
                    u = nx*w+ny
                    uf.Unite(u, v)
        for dx, dy in (-2, 0), (2, 0), (0, -2), (0, 2):
            nx, ny = x+dx, y+dy
            if 0 <= nx < h and 0 <= ny < w:
                mx, my = (nx+x)//2, (ny+y)//2
                if B[x][y] == B[nx][ny] and B[mx][my] < B[x][y]:
                    u = nx*w+ny
                    uf.Unite(u, v)
s = sx*w+sy
g = gx*w+gy
if uf.Same(s, g):
    print('YES')
else:
    print('NO')