func_code_string: #include <bits/stdc++.h>   using namespace std;   long long pow(long long b, long long e, long long m) {     long long t = 1;     for (; e; e >>= 1, b = b * b % m) e & 1 ? t = t * b % m : 0;     return t;   }   template <class T>   inline bool chkmin(T &a, T b) {     return a > b ? a = b, true : false;   }   template <class T>   inline bool chkmax(T &a, T b) {     return a < b ? a = b, true : false;   }   template <class T>   inline T sqr(T x) {     return x * x;   }   template <typename T>   T gcd(T x, T y) {     for (T t; x; t = x, x = y % x, y = t)       ;     return y;   }   template <class edge>   struct Graph {     vector<vector<edge> > adj;     Graph(int n) {       adj.clear();       adj.resize(n + 5);     }     Graph() { adj.clear(); }     void resize(int n) { adj.resize(n + 5); }     void add(int s, edge e) { adj[s].push_back(e); }     void del(int s, edge e) { adj[s].erase(find(iter(adj[s]), e)); }     vector<edge> &operator[](int t) { return adj[t]; }   };   int main() {     ios_base::sync_with_stdio(false);     int n, m;     cin >> n >> m;     if (m == 3) {       if (n == 3) {         cout <<  0 0  << endl <<  1 1  << endl <<  1 0  << endl;       } else if (n == 4) {         cout <<  0 0  << endl              <<  0 1  << endl              <<  -1 -1  << endl              <<  1 -1  << endl;       } else {         cout << -1 << endl;       }       return 0;     }     const int X = 1e7;     for (int i = 1; i <= m; ++i) {       cout << i <<     << +(X + i * i) << endl;     }     for (int i = 1; i <= n - m; ++i) {       cout << i <<     << -(X + i * i) << endl;     }     return 0;   }   