from collections import deque
H, W = map(int,input().split())
a, b = map(int,input().split())
s,t,x,y = map(int,input().split())
c, d = map(int,input().split())
s, t, x, y,c,d,a,b = s-1, t-1, x-1, y-1, c-1, d-1,a-1,b-1
li = [[10 ** 9] * W for _ in range(H)]
li[a][b] = 0

q = deque()
q.append((a, b))
h = [-1,0,1,0]
w = [0,1,0,-1]
while(q):
    p = q.popleft()
    for k in range(4):
        pos_x = p[0] + h[k]
        pos_y = p[1] + w[k]
        if(0 <= pos_x < H and 0 <= pos_y < W):
            if(li[pos_x][pos_y] == 10 ** 9):
                q.append((pos_x, pos_y))
                li[pos_x][pos_y] = li[p[0]][p[1]] + 1

num = 10 ** 9
for i in range(s, x+1):
    for j in range(t, y+1):
        if(num > li[i][j]):
            num = li[i][j]
            pos = [i, j]

print(num + abs(c - pos[0]) + abs(d- pos[1]) + abs(c - a) + abs(d - b))