#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
typedef long long ll;
const int INF = 1<<30;
const ll INFLL = 1LL<<60;
const ll MOD = 998244353;
const double INFD = 1.0E10;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, -1, 0, 1};
//const int dx[8] = {1, 1, 0, -1, -1, -1, 0, 1};
//const int dy[8] = {0, 1, 1, 1, 0, -1, -1, -1};
using Pair = pair<ll, ll>;
using Graph = vector<vector<ll, ll> >;
using mint = atcoder::modint998244353;


int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(15);
    int n; cin >> n;
    vector<ll> x(n), y(n);
    for (int i = 0; i < n; i++) cin >> x[i] >> y[i];
    int idx = 0, val = INF;
    for (int i = 0; i < n; i++){
        if (x[i] < val){
            idx = i;
            val = x[i];
        }
    }
    //cerr << idx << " " << x[idx] << " " << y[idx] << endl;
    vector<pair<ll, ll>> xy;
    for (int i = 0; i < n; i++){
        if (i != idx) xy.emplace_back(x[i] - x[idx], y[i] - y[idx]);
    }
    sort(xy.begin(), xy.end(), [](const auto &p1, const auto &p2){
        return atan2l(p1.second, p1.first) < atan2l(p2.second, p2.first);
    });
    
    mint ans = 0;
    for (int i = 0; i < n - 2; i++){
        auto [x1, y1] = xy[i];
        auto [x2, y2] = xy[i + 1];
        //cerr << x1 << y1 << x2 << y2 << " " << abs(x1 * y2 - x2 * y1) * mint(2).inv().val() << endl;;
        ans += mint(2).inv() * abs(x1 * y2 - x2 * y1);
    }
    
    cout << ans.val() << endl;
    
    return 0;
}