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()))))

    seen = [[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))
    while q:
        x, y = q.popleft()
        seen[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 seen[nx][ny]:
                continue
            if nx == gx and ny == gy:
                print("YES")
                exit()
            if i < 4:
                if abs(B[x][y] - B[nx][ny] > 1):
                    continue
            else:
                if B[x][y] != B[nx][ny]:
                    continue
            q.append((nx, ny))
    print("NO")


if __name__ == "__main__":
    main()