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#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;

template <class T>
void read(T &x)
{
    x = 0;
    register int c;
    while ((c = getchar()) && (c > '9' || c < '0'))
        ;
    for (; c >= '0' && c <= '9'; c = getchar())
        x = x * 10 + c - '0';
}

constexpr bool typetest = 0;
constexpr int N = 3e4 + 5;
constexpr int Inf = 1e9 + 7;

struct SegmentTree
{
    int n;
    int st[N * 4], lazy[N * 4];

    SegmentTree()
    {
        memset(st, 0, sizeof st);
        memset(lazy, 0, sizeof lazy);
    }

    void Update(int id, int l, int r, const int &a, const int &b, const int &v)
    {
        if (l > b || r < a)
            return;

        if (l >= a && r <= b)
        {
            lazy[id] += v;
            return;
        }

        Update(id << 1, l, (l + r) / 2, a, b, v);
        Update(id << 1 | 1, (l + r) / 2 + 1, r, a, b, v);

        st[id] = (lazy[id << 1] ? ((l + r) / 2 - l + 1) : st[id << 1]) + (lazy[id << 1 | 1] ? (r - (l + r) / 2) : st[id << 1 | 1]);
    }

    void Update(int l, int r, int v)
    {
        Update(1, 1, n, l + 1, r + 1, v);
    }
} f;

int n;
int x[N], y[N], z[N], t[N];
vector<pair<int, int>> in[N], out[N];

void Read()
{
    cin >> n;
    for (int i = 1; i <= n; ++i)
    {
        cin >> x[i] >> y[i] >> z[i] >> t[i];
        in[x[i]].emplace_back(y[i], t[i] - 1);
        out[z[i]].emplace_back(y[i], t[i] - 1);
    }
}

void Solve()
{
    f.n = 3e4;

    ll ans(0);

    for (int i = 0; i < 3e4; ++i)
    {
        for (auto j : in[i])
            f.Update(j.first, j.second, 1);
        for (auto j : out[i])
            f.Update(j.first, j.second, -1);

        ans += (f.lazy[1] ? f.n : f.st[1]);
    }

    cout << ans;
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t(1);
    if (typetest)
        cin >> t;
    for (int _ = 1; _ <= t; ++_)
    {
        //cout << "Case #" << _ << ": ";
        Read();
        Solve();
    }
    //cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
}