#include <bits/stdc++.h>   using namespace std;   template <class T>   inline T bigmod(T p, T e, T M) {     long long ret = 1;     for (; e > 0; e >>= 1) {       if (e & 1) ret = (ret * p) % M;       p = (p * p) % M;     }     return (T)ret;   }   template <class T>   inline T gcd(T a, T b) {     if (b == 0) return a;     return gcd(b, a % b);   }   template <class T>   inline T modinverse(T a, T M) {     return bigmod(a, M - 2, M);   }   long long bit[400001];   void add(int x, int v) {     for (int i = x; i <= 400000; i += i & -i) bit[i] += v;   }   long long query(int x) {     long long ret = 0;     for (int i = x; i > 0; i -= i & -i) ret += bit[i];     return ret;   }   long long ar[100001][4];   map<long long, long long> mx, my;   vector<pair<long long, long long> > horizontal[400001], vertical[400001];   vector<int> in[400001], out[400001];   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     int n;     cin >> n;     for (int i = (0); i < (n); ++i) {       for (int j = (0); j < (4); ++j) cin >> ar[i][j];       mx[ar[i][0]] = mx[ar[i][2]] = my[ar[i][1]] = my[ar[i][3]] = 1;       if (ar[i][0] > ar[i][2]) swap(ar[i][0], ar[i][2]);       if (ar[i][1] > ar[i][3]) swap(ar[i][1], ar[i][3]);     }     int c1 = 0, c2 = 0;     for (auto &v : mx) {       v.second = ++c1;     }     for (auto &v : my) {       v.second = ++c2;     }     for (int i = (0); i < (n); ++i) {       if (ar[i][0] == ar[i][2])         horizontal[mx[ar[i][0]]].push_back(make_pair(ar[i][1], ar[i][3]));       else         vertical[my[ar[i][1]]].push_back(make_pair(ar[i][0], ar[i][2]));     }     long long res = 0;     for (int i = 1; i <= c1; i++) {       sort(horizontal[i].begin(), horizontal[i].end());       if (horizontal[i].size() == 0) continue;       int last = 0;       for (int j = 1; j < horizontal[i].size(); j++) {         if (horizontal[i][j].first <= horizontal[i][last].second) {           horizontal[i][last].second =               max(horizontal[i][last].second, horizontal[i][j].second);         } else {           res += horizontal[i][last].second - horizontal[i][last].first + 1;           in[my[horizontal[i][last].first]].push_back(i);           out[my[horizontal[i][last].second]].push_back(i);           last = j;         }       }       res += horizontal[i][last].second - horizontal[i][last].first + 1;       in[my[horizontal[i][last].first]].push_back(i);       out[my[horizontal[i][last].second]].push_back(i);     }     for (int i = 1; i <= c2; i++) {       sort(vertical[i].begin(), vertical[i].end());       for (int j = 0; j < in[i].size(); j++) {         add(in[i][j], 1);       }       if (vertical[i].size() == 0) {         for (int j = 0; j < out[i].size(); j++) {           add(out[i][j], -1);         }         continue;       }       int last = 0;       for (int j = 1; j < vertical[i].size(); j++) {         if (vertical[i][j].first <= vertical[i][last].second) {           vertical[i][last].second =               max(vertical[i][last].second, vertical[i][j].second);         } else {           res += vertical[i][last].second - vertical[i][last].first + 1;           res -= query(mx[vertical[i][last].second]) -                  query(mx[vertical[i][last].first] - 1);           last = j;         }       }       res += vertical[i][last].second - vertical[i][last].first + 1;       res -= query(mx[vertical[i][last].second]) -              query(mx[vertical[i][last].first] - 1);       for (int j = 0; j < out[i].size(); j++) {         add(out[i][j], -1);       }     }     cout << res << endl;   }