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())


if R1<=A<=R2 and C1<=B<=C2:
    k = 0
    g = abs(A-P) + abs(B-Q)
else:
    Dirc = [[-1,0], [1, 0], [0,-1], [0,1]]
    V = [[0 for _ in range(W)] for _ in range(H)]
    dq = deque()
    Flag = False
    dq.append([A-1, B-1, 0])
    V[A-1][B-1] = 1
    while(dq):
        a = dq.popleft()
        for d in Dirc:
            x, y, k = a[0] + d[0], a[1]+d[1], a[2]
            if R1-1 <= x <= R2-1 and C1-1 <= y <= C2-1:
                Flag = True        
                break
            if 0<=x<H and 0<=y<W:
                if  V[x][y] == 0 :
                    dq.append([x,y,k+1])
                    V[x][y] = 1
        if Flag:
            k += 1
            break
    g = abs(P-1-x) + abs(Q-1-y) 
h = abs(A-P) + abs(B-Q)
ANS = k + g + h
print(ANS)

# print(k, g, h)