class DisjointSet(object):
    def __init__(self, n):
        self.parent = list(range(n))
        self.rank = [0] * n
        self.num = n  # number of disjoint sets

    def union(self, x, y):
        self._link(self.find_set(x), self.find_set(y))

    def _link(self, x, y):
        if x == y:
            return
        self.num -= 1
        if self.rank[x] > self.rank[y]:
            self.parent[y] = x
        else:
            self.parent[x] = y
            if self.rank[x] == self.rank[y]:
                self.rank[y] += 1

    def find_set(self, x):
        xp = self.parent[x]
        if xp != x:
            self.parent[x] = self.find_set(xp)
        return self.parent[x]


def read_data():
    h, w = map(int, input().split())
    sx, sy, gx, gy = map(int, input().split())
    bs = []
    for _ in range(h):
        b = input()
        bs.append(list(map(int, b)))
    return h, w, sx - 1, sy - 1, gx - 1, gy - 1, bs

def solve(h, w, sx, sy, gx, gy, bs):
    hw = h * w
    ds = DisjointSet(hw)
    for x in range(h):
        for y in range(w):
            pos = x * w + y
            b = bs[x][y]
            if x > 0 and abs(bs[x-1][y] - b) <= 1:
                ds.union(pos, pos - w)
            if y > 0 and abs(bs[x][y-1] - b) <= 1:
                ds.union(pos, pos - 1)
            if x > 1 and bs[x-2][y] == b and bs[x-1][y] < b:
                    ds.union(pos, pos - w * 2)
            if y > 1 and bs[x][y-2] == b and bs[x][y-1] < b:
                    ds.union(pos, pos - 2)
    s = sx * w + sy
    g = gx * w + gy
    if ds.find_set(s) == ds.find_set(g):
        print('YES')
    else:
        print('NO')

param = read_data()
solve(*param)