h,w=map(int,input().split())
int1=lambda x:int(x)-1
si,sj=map(int1,input().split())
gi,gj=map(int1,input().split())
F=[[0]*w for _ in range(h)]
ans=0
def dfs(x,y):
    global ans
    if (x,y)==(gi,gj):
        ans+=1
    else:
        F[x][y]=1
        for i,j in [(0,1),(0,-1),(1,0),(-1,0)]:
            nx,ny=x+i,y+j
            if 0<=nx<h and 0<=ny<w and F[nx][ny]==0:
                stc=0
                for ii, jj in [(0, 1), (0, -1), (1, 0), (-1, 0)]:
                    nnx, nny = nx + ii, ny + jj
                    if 0<=nnx<h and 0<=nny<w and F[nnx][nny]==1:
                        stc+=1
                if stc==1:
                    dfs(nx,ny)
        F[x][y]=0
dfs(si,sj)
print(ans)