#include<bits/stdc++.h>
#include<atcoder/all>
#define chmin(x,y) (x) = min((x),(y))
#define chmax(x,y) (x) = max((x),(y))z
using namespace std;
using namespace atcoder;
using ll = long long;
const ll mod = 998244353;
using mint = modint998244353;
using Graph = vector<vector<pair<int,ll>>>;
const vector<int> dx = {1,0,-1,0}, dy = {0,1,0,-1};

double dist(int x1, int y1, int x2, int y2){
  double res = (x1-x2) * (x1-x2) + (y1-y2) * (y1-y2);
  return sqrt(res);
}

ll need(ll n, ll m){
  ll res = 0;
  if(n < 0) return res;
  res = n / m;
  if(n % m > 0) res++;
  return res;
}

ll d2(ll x1, ll y1, ll x2, ll y2){
  // auto [x1,y1] = p;
  // auto [x2,y2] = q;
  ll res = (x1-x2) * (x1-x2) + (y1-y2) * (y1-y2);
  return res;
}

int main(){
  // input
  int H,W; cin >> H >> W;
  int si,sj,gi,gj;
  cin >> si >> sj >> gi >> gj;
  --si, --sj, --gi, --gj;
  
  // solve
  int ans = 0;
  // const pair<int,int> dummy = {-1,-1};
  //queue<vector<pair<int,int>>> q;
  queue<pair<int,ll>> q;
  q.emplace(si*W+sj,0LL);
  
  while(!q.empty()){
    auto[now,cant] = q.front();
    q.pop();
    int x = now / W, y = now % W;
    
    ll nxt_cant = cant;
    for(int i = 0; i < 4; i++){
      int nx = x + dx[i], ny = y + dy[i];
      if(nx < 0 || nx >= H || ny < 0 || ny >= W) continue; // grid hamidashi
      ll pos = 1LL << (nx * W + ny);
      nxt_cant |= pos;
    }
    
    for(int i = 0; i < 4; i++){
      int nx = x + dx[i], ny = y + dy[i];
      
      if(nx < 0 || nx >= H || ny < 0 || ny >= W) continue; // grid hamidashi
      ll pos = 1LL << (nx * W + ny);
      if(cant & pos) continue; // not saitan keiro
      
      if(nx == gi && ny == gj) ans++;
      else q.emplace(nx * W + ny, nxt_cant);
    }
  }
  
  // output
  cout << ans << endl;
}