from collections import deque

h, w = map(int, input().split())
a, b = map(int, input().split())
r1, c1, r2, c2 = map(int, input().split())
p, q = map(int, input().split())
a -= 1; b -= 1
r1 -= 1; r2 -= 1; c1 -= 1; c2 -= 1
p -= 1; q -= 1


dxy = [0, 1, 0, -1, 0]

length1 = [[10**18 for _ in range(w)] for _ in range(h)]
length1[a][b] = 0
queue = deque([(a, b)])
while len(queue) > 0:
    x, y = queue.popleft()
    for i in range(4):
        nx = x + dxy[i]
        ny = y + dxy[i+1]
        if 0 <= nx < h and 0 <= ny < w and length1[nx][ny] == 10**18:
            length1[nx][ny] = length1[x][y] + 1
            queue.append((nx, ny))

length2 = [[10**18 for _ in range(w)] for _ in range(h)]
length2[p][q] = 0
queue = deque([(p, q)])
while len(queue) > 0:
    x, y = queue.popleft()
    for i in range(4):
        nx = x + dxy[i]
        ny = y + dxy[i+1]
        if 0 <= nx < h and 0 <= ny < w and length2[nx][ny] == 10**18:
            length2[nx][ny] = length2[x][y] + 1
            queue.append((nx, ny))

ans = 10**18
for x in range(r1, r2+1):
    for y in range(c1, c2+1):
        tmp = length1[x][y] + length2[x][y] + length1[p][q]
        ans = min(ans, tmp)
        
print(ans)