#include <bits/stdc++.h>
using namespace std;

#define pb push_back
using ll = long long;

const int maxn = 510;
int x[maxn], y[maxn];
int n;
int cross(int i, int j, int k) {
    return (x[j] - x[i]) * (y[k] - y[i]) - (x[k] - x[i]) * (y[j] - y[i]);
}
vector<int> convex(vector<int> p) {
    sort(p.begin(), p.end(), [&](int a, int b) {
        return x[a] != x[b] ? x[a] < x[b] : y[a] < y[b];
    });
    static int s1[maxn], s2[maxn];
    int t1 = 0, t2 = 0;
    for (int i : p) {
        while (t1 >= 2 && cross(s1[t1 - 1], s1[t1], i) > 0) t1--;
        s1[++t1] = i;
    }
    for (int i : p) {
        while (t2 >= 2 && cross(s2[t2 - 1], s2[t2], i) < 0) t2--;
        s2[++t2] = i;
    }
    vector<int> ans;
    for (int i = 1; i <= t1; i++) {
        ans.pb(s1[i]);
    }
    while (t2 > 0 && s2[t2] == ans.back()) t2--;
    while (t2 > 0) ans.pb(s2[t2]), t2--;
    while (ans.size() >= 2 && ans[0] == ans.back()) ans.pop_back();
    return ans;
}
int inc[maxn];
int pos[maxn];
int ans = 0;
vector<int> safe[maxn];
int safemp[maxn][maxn];
int safemps[maxn][maxn];
vector<int> sortonconv[maxn];

void solve() {
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> x[i] >> y[i];
    }
    vector<int> conv, tmp;
    conv.resize(n);
    iota(conv.begin(), conv.end(), 1);
    conv = convex(conv);
    // for (int i : conv) cout << i << " ";
    // cout << "\n";
    auto ne = [&](int i) -> int {
        return i + 1 == conv.size() ? 0 : i + 1;
    };
    auto pre = [&](int i) -> int {
        return i == 0 ? ((int(conv.size())) - 1) : i - 1;
    };
    auto norm = [&](int i) -> int {
        return i % conv.size();
    };
    for (int i : conv) inc[i] = 1;
    for (int i = 1; i <= n; i++) {
        if (!inc[i]) tmp.pb(i);
    }
    for (int i = 0; i < conv.size(); i++) {
        pos[conv[i]] = i;
        sortonconv[i] = tmp;
        sort(sortonconv[i].begin(), sortonconv[i].end(), [&](int a, int b) {
            if (cross(conv[i], a, b) > 0) return 1;
            return 0;
        });
    }
    // 0
    ans++;
    // 1;

    for (int i = 1; i <= n; i++) {
        if (inc[i]) continue;
        for (int j = 0; j < conv.size(); j++) {
            int u = conv[j];
            int v = conv[ne(j)];
            int flag = 1;
            for (int k = 1; k <= n; k++) {
                if (inc[k] || i == k) continue;
                if (cross(i, v, k) > 0 && cross(i, k, u) > 0) {
                    flag = 0;
                    break;
                }
            }
            if (flag) {
                safe[i].pb(j);
                safemp[i][j] = 1;
                ans++;
            }
        }
        for (int j = 0; j < conv.size(); j++) {
            if (j - 1 >= 0) {
                safemps[i][j] = safemps[i][j - 1];
            }
            safemps[i][j] += safemp[i][j];
        }
    }
    // cerr << ans << "  0and1\n";
    function<int(int, int, int)> calcsafemp = [&](int i, int l, int r) -> int {
        if (r >= l) {
            return safemps[i][r] - (l == 0 ? 0 : safemps[i][l - 1]);
        } else {
            return calcsafemp(i, 0, r) + calcsafemp(i, l, ((int)(conv.size())) - 1);
        }
    };
    // 2.1
    int tmpans = 0;
    for (int i = 1; i <= n; i++) {
        if (inc[i]) continue;
        for (int j = 1; j <= n; j++) {
            if (inc[j] || i == j) continue;
            for (int k = 0; k < conv.size(); k++) {
                if (safemp[i][k] == 0) continue;
                // cout << i << " " << j << " " << k << " " << conv[k] << "#\n";
                int lasttmpans = tmpans;
                if (cross(conv[k], i, j) > 0) {
                    int l = ne(k);
                    int r = pre(k);
                    if (r < l) r += conv.size();
                    int ans = l;
                    while (l <= r) {
                        int mid = l + r >> 1;
                        if (cross(j, i, conv[ne(norm(mid))]) > 0 || cross(conv[k], i, conv[ne(norm(mid))]) > 0) {
                            ans = mid;
                            l = mid + 1;
                        } else {
                            r = mid - 1;
                        }
                    }
                    tmpans += calcsafemp(j, ne(k), norm(ans));
                } else if (cross(conv[ne(k)], i, j) > 0) {
                    tmpans += calcsafemp(j, ne(k), pre(k));
                } else {
                    int l = ne(k), r = pre(k);
                    if (r < l) r += conv.size();
                    int ans = r;
                    while (l <= r) {
                        int mid = l + r >> 1;
                        if (cross(j, i, conv[norm(mid)]) < 0 || cross(conv[k], i, conv[norm(mid)]) < 0) {
                            ans = mid;
                            r = mid - 1;
                        } else {
                            l = mid + 1;
                        }
                    }
                    tmpans += calcsafemp(j, norm(ans), pre(k));
                }
                // cout << tmpans - lasttmpans << "%\n";
            }
        }
    }

    assert(tmpans % 2 == 0);
    ans += tmpans /= 2;
    // cerr << ans << "  0 and 1 and 2.1\n";
    // 2.2
    tmpans = 0;
    for (int j = 0; j < conv.size(); j++) {
        for (int id = 0; id < sortonconv[j].size(); id++) {
            int i = sortonconv[j][id];
            // cout<<i<<"  oo\n";
            if(safemp[i][j]){
                int cur = -1;
                for (int kd = id - 1; kd >= 0; kd--) {
                    int k = sortonconv[j][kd];
                    if (cur == -1 || cross(i, cur, k) < 0) {
                        cur = k;
                        if (cross(conv[ne(j)], i, k) > 0) {
                            ans++;
                            // cout  << conv[j] << " "<<conv[ne(j)]<<" " << i << " " << cur << " +1  $\n";
                        } else {
                            tmpans++;
                            // cout << conv[j] << " " << conv[ne(j)] << " " << i << " " << cur << " +1/2  $\n";
                        }
                    }
                }

            }
            if(safemp[i][pre(j)]){
                // cout<<"??\n";
                int cur = -1;
                for (int kd = id + 1; kd < sortonconv[j].size(); kd++) {
                    int k = sortonconv[j][kd];
                    if (cur == -1 || cross(i, cur, k) > 0) {
                        cur = k;
                        if (cross(conv[pre(j)], i, k) > 0) {
                            tmpans++;
                            // cout << conv[pre(j)]<< " " << conv[j] << " " << i << " " << cur << " +1/2  %\n";
                        } else {
                            ans++;
                            // cout << conv[pre(j)]<< " " << conv[j] << " " << i << " " << cur << " +1  %\n";
                        }
                    }
                }

            }
            // cout<<"@\n";
        }
    }
    ans += tmpans / 2;
    cout << ans << "\n";
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    int t = 1;
    // cin >> t;
    while (t--) solve();
    return 0;
}
/*
5
4 0
0 0
2 1
3 3
3 1
*/