#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
int add(int a, int b) {
  long long x = a + b;
  if (x >= 1000000009) x -= 1000000009;
  if (x < 0) x += 1000000009;
  return x;
}
long long mul(long long a, long long b) { return (a * b) % 1000000009; }
long long pw(long long a, long long b) {
  long long ans = 1;
  while (b) {
    if (b & 1) ans = (ans * a) % 1000000009;
    a = (a * a) % 1000000009;
    b >>= 1;
  }
  return ans;
}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
long long rand_seed() {
  long long a = rng();
  return a;
}
int n;
map<int, pair<int, int> > pos;
map<pair<int, int>, int> id;
vector<set<int> > p, ch;
bool canrem(int i) {
  int ok = 1;
  for (auto j : p[i]) ok &= (ch[j].size() > 1);
  return ok;
}
void rem(int i) {
  for (auto j : p[i]) ch[j].erase(i);
  for (auto j : ch[i]) p[j].erase(i);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n;
  p.resize(n);
  ch.resize(n);
  for (int x, y, i = 0; i < n; i++) {
    cin >> y >> x;
    pos[i] = {x, y};
    id[{x, y}] = i;
  }
  for (int i = 0; i < n; i++) {
    int x = pos[i].first, y = pos[i].second;
    for (int z = -1; z < 2; z++) {
      if (id.count({x + 1, y + z})) p[i].insert(id[{x + 1, y + z}]);
      if (id.count({x - 1, y + z})) ch[i].insert(id[{x - 1, y + z}]);
    }
  }
  set<int> can;
  for (int i = 0; i < n; i++) {
    int x = pos[i].first, y = pos[i].second;
    if (canrem(i)) can.insert(i);
  }
  long long ans = 0;
  for (int i = 0; i < n; i++) {
    int j;
    if (i % 2 == 0)
      j = *can.rbegin();
    else
      j = *can.begin();
    ans = mul(ans, n);
    ans = add(ans, j);
    int x = pos[j].first;
    int y = pos[j].second;
    rem(j);
    can.erase(j);
    id.erase(pos[j]);
    for (int z = -2; z < 3; z++) {
      if (id.count({x, y + z})) can.erase(id[{x, y + z}]);
      if (id.count({x - 1, y + z})) can.erase(id[{x - 1, y + z}]);
    }
    for (int z = -2; z < 3; z++) {
      if (id.count({x, y + z}) && canrem(id[{x, y + z}]))
        can.insert(id[{x, y + z}]);
      x--;
      if (id.count({x, y + z}) && canrem(id[{x, y + z}]))
        can.insert(id[{x, y + z}]);
      x++;
    }
  }
  cout << ans;
  return 0;
}
