from collections import defaultdict, deque, Counter
# from functools import cache
# import copy
from itertools import combinations, permutations, product, accumulate, groupby, chain
# from more_itertools import distinct_permutations
from heapq import heapify, heappop, heappush
import math
import bisect
# from pprint import pprint
from random import randint, shuffle, randrange
# from sortedcontainers import SortedSet, SortedList, SortedDict
import sys
# sys.setrecursionlimit(2000000)
input = lambda: sys.stdin.readline().rstrip('\n')
inf = float('inf')
mod1 = 10**9+7
mod2 = 998244353
def ceil_div(x, y): return -(-x//y)

#################################################   

def ok(ni, nj, i, j):
    if not (0 <= ni < H and 0 <= nj < W) or been[ni][nj]: return False
    for di, dj in D:
        if not (0 <= ni+di < H and 0 <= nj+dj < W): continue
        if ni+di == i and nj+dj == j: continue
        if been[ni+di][nj+dj]: return False
    return True

H, W = map(int, input().split())
si, sj = map(lambda x: int(x)-1, input().split())
ti, tj = map(lambda x: int(x)-1, input().split())

D = [(0, 1), (0, -1), (1, 0), (-1, 0)]
been = [[False]*W for _ in range(H)]
stack = [(si, sj)]
ans = 0
while stack:
    i, j = stack.pop()
    if i >= 0:
        if i == ti and j == tj:
            ans += 1
            continue
        been[i][j] = True
        stack.append((~i, j))
        for di, dj in D:
            ni, nj = i+di, j+dj
            if ok(ni, nj, i, j):
                stack.append((ni, nj))
    else:
        i = ~i
        been[i][j] = False
print(ans)