#include <bits/stdc++.h>
const int inf = 0;
const double eps = 0;
const int ms = 0;
const int md = 0;
const int MOD = 1e9 + 7;
using namespace std;
long long nChoosek(long long n, long long k) {
  if (k > n) return 0;
  if (k * 2 > n) k = n - k;
  if (k == 0) return 1;
  long long result = n;
  for (int i = 2; i <= k; ++i) {
    result *= (n - i + 1);
    result /= i;
  }
  return result;
}
long long binpow(long long a, long long b) {
  if (b == 0) return 1;
  if (b % 2 == 1) {
    return binpow(a, b - 1) * a % MOD;
  } else {
    long long b2 = binpow(a, b / 2) % MOD;
    return b2 * b2 % MOD;
  }
}
void solve() {
  int nn;
  cin >> nn;
  int total = 0;
  if (nn == 1) {
    cout << 7 << endl;
    cout << 0 << " " << 0 << endl;
    cout << 0 << " " << 1 << endl;
    cout << 1 << " " << 0 << endl;
    cout << 1 << " " << 1 << endl;
    cout << 1 << " " << 2 << endl;
    cout << 2 << " " << 1 << endl;
    cout << 2 << " " << 2 << endl;
    return;
  }
  int n = (nn - (nn % 2)) / 2;
  cout << 2 + 7 * n + 1 + 6 + 3 * n + 1 + 7 * (nn % 2) << endl;
  cout << 0 << " " << -1 << endl;
  cout << 0 << " " << -2 << endl;
  for (int i = 0; i < 3 * n; i++) {
    cout << 0 << " " << i << endl;
    if (i % 3 != 2) {
      cout << 1 << " " << i << endl;
      cout << -1 << " " << i << endl;
    }
  }
  cout << 0 << " " << 3 * n << endl;
  for (int i = 0; i < 3; i++) {
    cout << i + 1 << " " << -2 << endl;
    cout << i + 1 << " " << 3 * n << endl;
  }
  for (int i = 0; i < 3 * n + 1; i++) {
    cout << 3 << " " << i - 1 << endl;
  }
  if (nn % 2 == 1) {
    cout << -1 << " " << -2 << endl;
    cout << -2 << " " << -2 << endl;
    cout << -2 << " " << -3 << endl;
    cout << -2 << " " << -4 << endl;
    cout << -1 << " " << -4 << endl;
    cout << 0 << " " << -4 << endl;
    cout << 0 << " " << -3 << endl;
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int t;
  t = 1;
  while (t--) {
    solve();
  }
}
