#!/usr/bin/env python3

import collections


DELTA_1 = [(1, 0), (-1, 0), (0, 1), (0, -1)]


def can_escape(height, width, start, goal, stage):
    def out_of_stage(r, c):
        return r < 0 or r >= height or c < 0 or c >= width
    visited = collections.defaultdict(bool)
    visited[start] = True
    q = collections.deque()
    q.append(start)
    while q:
        r0, c0 = q.popleft()
        if (r0, c0) == goal:
            return True
        for dr, dc in DELTA_1:
            r, c = r0 + dr, c0 + dc
            if out_of_stage(r, c):
                continue
            elif abs(stage[r][c] - stage[r0][c0]) <= 1 and not visited[(r, c)]:
                visited[(r, c)] = True
                q.append((r, c))
            r2, c2 = r0 + 2 * dr, c0 + 2 * dc
            if out_of_stage(r2, c2):
                continue
            elif stage[r2][c2] == stage[r0][c0] > stage[r][c]:
                if not visited[(r2, c2)]:
                    visited[(r2, c2)] = True
                    q.append((r2, c2))
    else:
        return False


def main():
    height, width = map(int, input().split())
    sx, sy, gx, gy = map(lambda x: int(x) - 1, input().split())
    start = sx, sy
    goal = gx, gy
    stage = [list(map(int, input())) for _ in range(height)]
    if can_escape(height, width, start, goal, stage):
        print("YES")
    else:
        print("NO")


if __name__ == '__main__':
    main()