H, W = map(int, input().split())
si, sj = map(int, input().split())
si -= 1
sj -= 1
r1, c1, r2, c2 = map(int, input().split())
r1 -= 1
c1 -= 1
r2 -= 1
c2 -= 1
ti, tj = map(int, input().split())
ti -= 1
tj -= 1

from collections import deque
que = deque()
dij = [(1,0),(0,1),(-1,0),(0,-1)]

musi = set()
for i in range(r1, r2+1):
    for j in range(c1, c2+1):
        musi.add((i,j))

visited = set()
que.append((si,sj,0))
visited.add((si,sj))
while que:
    nowi, nowj, d = que.popleft()
    if (nowi, nowj) in musi:
        d0 = d
        break
    for di, dj in dij:
        toi, toj = nowi+di, nowj+dj
        if toi < 0 or toi >= H or toj < 0 or toj >= W:
            continue
        if (toi,toj) not in visited:
            visited.add((toi,toj))
            que.append((toi, toj, d+1))

visited = set()
que = deque()
que.append((nowi, nowj, 0))
visited.add((nowi, nowj))
while que:
    nowi, nowj, d = que.popleft()
    if (nowi, nowj) == (ti, tj):
        d1 = d
        break
    for di, dj in dij:
        toi, toj = nowi+di, nowj+dj
        if toi < 0 or toi >= H or toj < 0 or toj >= W:
            continue
        if (toi,toj) not in visited:
            visited.add((toi,toj))
            que.append((toi, toj, d+1))

visited = set()
que = deque()
que.append((nowi, nowj, 0))
visited.add((nowi, nowj))
while que:
    nowi, nowj, d = que.popleft()
    if (nowi, nowj) == (si, sj):
        d2 = d
        break
    for di, dj in dij:
        toi, toj = nowi+di, nowj+dj
        if toi < 0 or toi >= H or toj < 0 or toj >= W:
            continue
        if (toi,toj) not in visited:
            visited.add((toi,toj))
            que.append((toi, toj, d+1))

# print(musi)
print(d0+d1+d2)