#include <bits/stdc++.h>
using namespace std;
const int iinf = INT_MAX;
const long long linf = 9223372036854775807LL;
void pd(int n) {
  cout << n - 1 << " -1\n";
  cout << n - 1 << " -2\n";
  cout << n << " -2\n";
  cout << n + 1 << " -1\n";
  cout << n + 1 << " -2\n";
}
void pu(int n) {
  cout << n - 1 << " 1\n";
  cout << n - 1 << " 2\n";
  cout << n << " 2\n";
  cout << n + 1 << " 1\n";
  cout << n + 1 << " 2\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int tc = 1;
  while (tc--) {
    int n;
    cin >> n;
    cout << 15 + (n - 1) * 7 << endl;
    int i = 0;
    int p = 0;
    while (p < (15 + (n - 1) * 7)) {
      cout << i << " 0\n";
      ++p;
      if ((i - 1) % 4 == 0) {
        pd(i);
        p += 5;
      }
      if ((i - 3) % 4 == 0) {
        pu(i);
        p += 5;
      }
      i++;
    }
  }
  return 0;
}
