import pprint
from collections import deque

def main():
    h, w = map(int, input().split())
    sx, sy, gx, gy = map(int, input().split())
    sx -= 1
    sy -= 1
    gx -= 1
    gy -= 1

    B = []
    for i in range(h):
        B.append(list(map(int, list(input()))))

    if(sx == gx and sy == gy):
        print("YES")
        exit()

    seen1 = [[False for _ in range(w)] for _ in range(h)]
    seen2 = [[False for _ in range(w)] for _ in range(h)]

    dx = [-1, 1, 0, 0, -2, 2, 0, 0]
    dy = [0, 0, -1, 1, 0, 0, -2, 2]

    q = deque()
    q.append((sx, sy, 0))
    while q:
        x, y, z = q.popleft()
        if z == 0:
            seen1[x][y] = True
            seen2[x][y] = True
        elif z == 1:
            seen1[x][y] = True
        elif z == 2:
            seen2[x][y] = True
        
        for i in range(8):
            nx = x + dx[i]
            ny = y + dy[i]
            if nx < 0 or nx >= h or ny < 0 or ny >= w:
                continue

            if i < 4:
                if abs(B[x][y] - B[nx][ny]) <= 1 and seen1[nx][ny] == False:
                    if nx == gx and ny == gy:
                        print("YES")
                        exit()
                    else:
                        q.append((nx, ny, 1))
            else:
                if B[x][y] == B[nx][ny] and seen2[nx][ny] == False:
                    if nx == gx and ny == gy:
                        print("YES")
                        exit()
                    else:
                        q.append((nx, ny, 2))
    print("NO")


if __name__ == "__main__":
    main()