func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long inf = LONG_MAX;   const long long arr = 1000000;   bool comp(pair<string, long long> a, pair<string, long long> b) {     return a.second > b.second;   }   int main(void) {     long long n;     cin >> n;     vector<pair<long long, long long> > v;     for (int i = 0; i < n + 1; i++) {       long long x, y;       cin >> x >> y;       v.push_back({x, y});     }     long long ans = 0;     for (int i = 1; i < n; i++) {       long long x1 = v[i - 1].first, y1 = v[i - 1].second;       long long x2 = v[i].first, y2 = v[i].second;       long long x3 = v[i + 1].first, y3 = v[i + 1].second;       if (x1 == x2 && y2 > y1) {         if (x3 < x1 && y3 > y1) ans++;       }       if (y1 == y2 && x2 > x1) {         if (x3 > x1 && y3 > y1) ans++;       }       if (x1 == x2 && y2 < y1) {         if (x3 > x1 && y3 < y1) ans++;       }       if (y1 == y2 && x2 < x1) {         if (x3 < x1 && y3 < y1) ans++;       }     }     cout << ans <<   n ;     return 0;   }   