from collections import deque

MAX_INT = 10 ** 18

def solve(H, W, s_r, s_c):
    dists = [[MAX_INT for _ in range(W)] for _ in range(H)]
    queue = deque()
    dists[s_r][s_c] = 0
    queue.append((s_r, s_c))
    while len(queue) > 0:
        r, c = queue.popleft()

        for dr, dc in ((-1, 0), (1, 0), (0 , -1), (0, 1)):
            new_r = dr + r
            new_c = dc + c
            if 0 <= new_r < H and 0 <= new_c < W:
                if dists[new_r][new_c] == MAX_INT:
                    dists[new_r][new_c] = dists[r][c] + 1
                    queue.append((new_r, new_c))
    return dists



def main():
    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())


    dists_ab = solve(H, W, A - 1, B - 1)
    dists_pq = solve(H, W, P - 1, Q - 1)

    answer = MAX_INT
    for r in range(R1 - 1, R2):
        for c in range(C1 - 1, C2):
            ans = dists_ab[r][c] + dists_pq[r][c] + dists_pq[A - 1][B - 1]
            answer = min(ans, answer)
    print(answer)





if __name__ == "__main__":
    main()
#    main2()