Nguyễn Việt Quang

include<bits/stdc++.h>

using namespace std;

long long kt(long long n) { if (n >= 0) return n / 2; else return (n - 1) / 2; }

long long ck(long long a, long long b) { if (a > b) { return 0; } return kt(b) - kt(a - 1); }

int main() { iosbase::syncwith_stdio(false); cin.tie(NULL);

int n;
cin >> n;

long long u1 = -1e10;
long long u2 = 1e10;
long long v1 = -1e10;
long long v2 = 1e10;

for (int i = 0; i < n; ++i) {
    long long xa, ya, xb, yb, xc, yc, xd, yd;
    cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd;

    long long cur_u1 = min({xa + ya, xb + yb, xc + yc, xd + yd});
    long long cur_u2 = max({xa + ya, xb + yb, xc + yc, xd + yd});
    long long cur_v1 = min({xa - ya, xb - yb, xc - yc, xd - yd});
    long long cur_v2 = max({xa - ya, xb - yb, xc - yc, xd - yd});

    u1 = max(u1, cur_u1);
    u2 = min(u2, cur_u2);
    v1 = max(v1, cur_v1);
    v2 = min(v2, cur_v2);
}

long long us = u1 + 1;
long long ue = u2 - 1;
long long vs = v1 + 1;
long long ve = v2 - 1;

if (us > ue || vs > ve) {
    cout << 0 << endl;
    return 0;
}

long long ul = ue - us + 1;
long long eu = ck(us, ue);
long long ou = ul - eu;

long long vl = ve - vs + 1;
long long ev = ck(vs, ve);
long long ov = vl - ev;

long long ans = (eu * ev) + (ou * ov);

cout << ans << endl;

return 0;

}