class UnionFind():
    def __init__(self, n):
        self.n = n
        self.par = list(range(self.n))
        self.rank = [1] * n
        self.count = n

    def find(self, x):
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]

    def unite(self, x, y):
        p = self.find(x)
        q = self.find(y)
        if p == q:
            return None
        if p > q:
            p, q = q, p
        self.rank[p] += self.rank[q]
        self.par[q] = p
        self.count -= 1

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def size(self, x):
        return self.rank[x]

    def count(self):
        return self.count

h, w = map(int, input().split())
sx, sy, gx, gy = map(int, input().split())
s = [list(map(int, list(input()))) for i in range(h)]
UF = UnionFind(h * w)
for i in range(h):
    for j in range(w - 1):
        if abs(s[i][j] - s[i][j + 1]) <= 1:
            UF.unite(i * w + j, i * w + j + 1)
        if j != w - 2 and s[i][j] == s[i][j + 2] > s[i][j + 1]:
            UF.unite(i * w + j, i * w + j + 2)
for i in range(h - 1):
    for j in range(w):
        if abs(s[i][j] - s[i + 1][j]) <= 1:
            UF.unite(i * w + j, (i + 1) * w + j)
        if i != h - 2 and s[i][j] == s[i + 2][j] > s[i + 1][j]:
            UF.unite(i * w + j, (i + 2) * w + j)
print("YES" if UF.same((sx - 1) * w + (sy - 1), (gx - 1) * w + (gy - 1)) else "NO")