func_code_string: #include <bits/stdc++.h>   using namespace std;   long long gcd(long long a, long long b) {     if (b == 0) return a;     return gcd(b, a % b);   }   template <typename A, size_t N, typename T>   void Fill(A (&array)[N], const T &val) {     std::fill((T *)array, (T *)(array + N), val);   }   class Graph {    public:     int vn;     int sumcost = 0;     vector<vector<pair<int, int>>> g;     Graph(int n) {       vn = n;       g.resize(n);     }     virtual void con(int a, int b, int w) = 0;     int getWeight(int f, int t) {       auto itr = lower_bound((g[f]).begin(), (g[f]).end(), make_pair(t, INT_MIN));       if (itr != g[f].end()) return itr->second;       return INT_MIN;     }     int Costsum() { return sumcost; }     void scan(int edcount, bool oindexed, bool w) {       for (int i = (0); (edcount) > i; i++) {         int a, b, c = 1;         scanf( %d %d , &a, &b);         if (w) scanf( %d , &c);         con(a - oindexed, b - oindexed, c);       }     }   };   class BiDGraph : public Graph {    public:     BiDGraph(int n) : Graph(n) {}     void con(int a, int b, int w = 1) {       g[a].push_back({b, w});       g[b].push_back({a, w});       sumcost++;     }   };   class DGraph : public Graph {    public:     DGraph(int n) : Graph(n) {}     void con(int a, int b, int w = 1) {       g[a].push_back({b, w});       sumcost++;     }   };   signed main() {     int n;     scanf( %d , &n);     printf( %d n , (n - 1) / 2);     return 0;   }   