#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n;
  cin >> n;
  vector<pair<int, int> > points;
  points.push_back({0, 0});
  for (int i = 1; i <= 2 * n; i++) {
    points.push_back({i, 0});
    if ((i & 1)) {
      points.push_back({i, 1});
      points.push_back({i, -1});
    }
  }
  points.push_back({1, 2});
  points.push_back({0, 2});
  points.push_back({-1, 2});
  points.push_back({-1, 1});
  points.push_back({-1, 0});
  if (!(n & 1)) {
    points.push_back({2 * n + 1, 0});
    points.push_back({2 * n + 1, 1});
    points.push_back({2 * n + 1, 2});
    points.push_back({2 * n, 2});
    points.push_back({2 * n - 1, 2});
    for (int i = 3; i < 2 * n - 3; i += 4) {
      points.push_back({i, 2});
      points.push_back({i + 1, 2});
      points.push_back({i + 2, 2});
    }
    for (int i = 1; i < 2 * n; i += 4) {
      points.push_back({i, -2});
      points.push_back({i + 1, -2});
      points.push_back({i + 2, -2});
    }
  } else {
    points.push_back({2 * n + 1, 0});
    points.push_back({2 * n + 1, -1});
    points.push_back({2 * n + 1, -2});
    points.push_back({2 * n, -2});
    points.push_back({2 * n - 1, -2});
    for (int i = 3; i < 2 * n; i += 4) {
      points.push_back({i, 2});
      points.push_back({i + 1, 2});
      points.push_back({i + 2, 2});
    }
    for (int i = 1; i < 2 * n - 3; i += 4) {
      points.push_back({i, -2});
      points.push_back({i + 1, -2});
      points.push_back({i + 2, -2});
    }
  }
  cout << points.size() << endl;
  for (pair<int, int>& point : points) {
    cout << point.first << " " << point.second << endl;
  }
  return;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  srand(chrono::steady_clock::now().time_since_epoch().count());
  int t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
