# https://yukicoder.me/problems/no/1219

from collections import deque

def main():
    h, w = map(int, input().split())
    sx, sy, gx, gy = map(int, input().split())
    B = []
    for _ in range(h):
        row = input()
        row = [int(x) for x in row]
        B.append(row)
    
    sx -= 1
    sy -= 1
    gx -= 1
    gy -= 1
    dists = [[False] * w for _ in range(h)]
    dists[sx][sy] = True
    queue = deque()
    queue.append((sx, sy))
    while len(queue) > 0:
        x, y = queue.popleft()
        height = B[x][y]
        for dx, dy in [(1, 0), (-1, 0), (0, 1), (0, -1)]:
            nx = x + dx
            ny = y + dy
            if nx < 0 or nx >= h or ny < 0 or ny >= w:
                continue

            if abs(B[nx][ny] - height) <= 1 and dists[nx][ny] == False:
                dists[nx][ny] = True
                queue.append((nx, ny))
        
        for dx, dy in [(1, 0), (-1, 0), (0, 1), (0, -1)]:
            nx = x + 2 * dx
            ny = y + 2 * dy
            if nx < 0 or nx >= h or ny < 0 or ny >= w:
                continue
            nx1 = x + dx
            ny1 = y + dy
            if height == B[nx][ny] and B[nx1][ny1] < height:
                if dists[nx][ny] == False:
                    dists[nx][ny] = True
                    queue.append((nx, ny))
    
    if dists[gx][gy]:
        print("YES")
    else:
        print("NO")







if __name__ == "__main__":
    main()