func_code_string: #include <bits/stdc++.h>   using namespace std;   pair<int, int> afis[1503];   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     int n, cnt = 0, i, x = 1;     cin >> n;     afis[++cnt] = {0, 0};     while (x <= n + 1) {       afis[++cnt] = {x, x};       afis[++cnt] = {x, x - 1};       afis[++cnt] = {x - 1, x};       x++;     }     cout << cnt <<   n ;     for (i = 1; i <= cnt; i++)       cout << afis[i].first <<     << afis[i].second <<   n ;     return 0;   }   