#include <iostream>
#include <vector>
#include <string>
#include <iomanip>
#include <queue>
#include <cmath>
#include <algorithm>
#include <unordered_map>
#include <tuple>
#include <iomanip>
#include <stdio.h>
#include <map>
#include <bitset>
#include <set>
#include <stack>
#include <queue>
#include <unordered_set>
#include <cassert>
#include <stdlib.h>
#include <time.h>
#include <random>


//#pragma GCC optimize("Ofast,no-stack-protector")
//#pragma GCC target("sse,sse2,sse3,sse3,sse4")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("fast-math")
//#pragma GCC target("avx2")
//#pragma GCC optimize("section-anchors")
//#pragma GCC optimize("profile-values,profile-reorder-functions,tracer")
//#pragma GCC optimize("vpt")
//#pragma GCC optimize("rename-registers")
//#pragma GCC optimize("move-loop-invariants")
//#pragma GCC optimize("unswitch-loops")
//#pragma GCC optimize("function-sections")
//#pragma GCC optimize("data-sections")

#define int long long
#define ll long long
#define ull unsigned long long
#define all(a) (a).begin(), (a).end()
#define pii pair<int, int>
#define pb push_back
#define ld long double


using namespace std;

const int INF = 1e17;
//const int mod = 2600000069;
//const int p = 179;

struct point {
    int x, y;
    point() {}
    point(int x_, int y_) {
        x = x_;
        y = y_;
    }
};

struct event {
    int type;
    point a;
    event() {}
    event(int type_, point a_) {
        type = type_;
        a = a_;
    }
};

int n;
vector<pair<point, point>> vert, hor;
vector<int> y;
int y_cnt = 0;
vector<event> x_events, y_events;
map<int, int> y_ind;

int ans = 0, y_events_ind = 0, y_events_size;

bool comp_x(event a, event b) {
    if (a.a.x == b.a.x) return a.type < b.type;
    return a.a.x < b.a.x;
}

bool comp_y(event a, event b) {
    if (a.a.x == b.a.x) {
        if (a.a.y == b.a.y) {
            return a.type < b.type;
        }
        return a.a.y < b.a.y;
    }
    return a.a.x < b.a.x;
}

struct node {
    int min = 0, cnt = 1;
    node() {}
    node (int min_, int cnt_) {
        min = min_;
        cnt = cnt_;
    }
};

vector<node> t;
vector<int> mod;

void in() {
    cin >> n;
    point a, b;
    for (int i = 0; i < n; i++) {
        cin >> a.x >> a.y >> b.x >> b.y;
        if (a.x == b.x) {
            if (a.y > b.y) swap(a, b);
            vert.pb({a, b});
            y.pb(a.y);
            y.pb(b.y);
            x_events.pb(event(2, point(a.x, 0)));
            y_events.pb(event(0, a));
            y_events.pb(event(1, b));
        } else {
            if (a.x > b.x) swap(a, b);
            hor.pb({a, b});
            y.pb(a.y);
            x_events.pb(event(0, a));
            x_events.pb(event(1, b));
        }
    }
    sort(all(x_events), comp_x);
    sort(all(y_events), comp_y);
    sort(all(y));
    y.resize(unique(all(y)) - y.begin());
    y_cnt = y.size();
    t.resize(8 * y_cnt);
    mod.resize(8 * y_cnt);
    for (int i = 0; i < y_cnt; i++) {
        y_ind[y[i]] = i;
    }
    y_events_size = y_events.size();
}


node merge(node a, node b) {
    node c;
    if (a.min == b.min) {
        c = a;
        c.cnt += b.cnt;
    } else if (a.min < b.min) c = a;
    else c = b;
    return c;
}


void push(int v) {
    mod[2 * v + 1] += mod[v];
    mod[2 * v + 2] += mod[v];
    t[v].min += mod[v];
    mod[v] = 0;
}

void build(int v, int l, int r) {
    if (r - l == 1) {
        t[v].cnt = 1;
        t[v].min = 0;
        return;
    }
    int m = (l + r) / 2;
    build(2 * v + 1, l, m);
    build(2 * v + 2, m, r);
    t[v] = merge(t[2 * v + 1], t[2 * v + 2]);
}

void update(int v, int l, int r, int askl, int askr, int val) {
    if (l >= askr || r <= askl) return;
    if (l >= askl && r <= askr) {
        mod[v] += val;
        push(v);
        return;
    }
    push(v);
    int m = (l + r) / 2;
    update(2 * v + 1, l, m, askl, askr, val);
    update(2 * v + 2, m, r, askl, askr, val);
    t[v] = merge(t[2 * v + 1], t[2 * v + 2]);
}

node sum(int v, int l, int r, int askl, int askr) {
    if (l >= askr || r <= askl) return node(INF, 0);
    push(v);
    if (l >= askl && r <= askr) return t[v];
    int m = (l + r) / 2;
    return merge(sum(2 * v + 1, l, m, askl, askr), sum(2 * v + 2, m, r, askl, askr));
}

node q;

void scanline_y(int x) {
    if (y_events_ind == y_events_size) return;
    int open = 0;
    int lst = y_events[y_events_ind].a.y;
    for (; y_events_ind < y_events_size && y_events[y_events_ind].a.x == x;) {
        while (y_events_ind < y_events_size && y_events[y_events_ind].a.x == x && y_events[y_events_ind].type == 0) {open++; y_events_ind++;}
        while (y_events_ind < y_events_size && y_events[y_events_ind].a.x == x && y_events[y_events_ind].type == 1) {open--; y_events_ind++;}
        if (open == 0) {
            q = sum(0, 0, y_cnt, y_ind[lst], y_ind[y_events[y_events_ind - 1].a.y] + 1);
            if (q.min == 0) {
                ans += y_events[y_events_ind - 1].a.y - lst + 1 - (y_ind[y_events[y_events_ind - 1].a.y] - y_ind[lst] + 1);
                if (q.min == 0) ans += q.cnt;
            }
            if (y_events_ind < y_events_size) lst = y_events[y_events_ind].a.y;
        }
    }
}


void scanline_x() {
    build(0, 0, y_cnt);
    int sz = x_events.size(), x, lst = x_events[0].a.x;
    for (int i = 0; i < sz;) {
        x = x_events[i].a.x;
        if (x_events[i].type == 2) {
            scanline_y(x);
            i++;
            continue;
        }
        q = sum(0, 0, y_cnt, 0, y_cnt);
        ans += y_cnt * (x - lst);
        if (t[0].min == 0) ans -= t[0].cnt * (x - lst);
        while (i < sz && x_events[i].a.x == x && x_events[i].type == 0) {
            update(0, 0, y_cnt, y_ind[x_events[i].a.y], y_ind[x_events[i].a.y] + 1, 1);
            i++;
        }
        q = sum(0, 0, y_cnt, 0, y_cnt);
        ans += y_cnt;
        if (t[0].min == 0) ans -= t[0].cnt;
        scanline_y(x);
        while (i < sz && x_events[i].a.x == x && x_events[i].type == 1) {
            update(0, 0, y_cnt, y_ind[x_events[i].a.y], y_ind[x_events[i].a.y] + 1, -1);
            i++;
        }
        while (i < sz && x_events[i].a.x == x) i++;
        lst = x + 1;
    }
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    in();
//    for (auto k : y) {
//        cout << k << " ";
//    }
//    cout << "\n";
    scanline_x();
    cout << ans;
}
/*
2
0 1 2 1
0 3 2 3

2
0 0 0 1
0 1 0 2

3
0 1 2 1
0 3 2 3
1 4 1 2


*/