func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int x[100005], y[100005];     int i, n, d = 0, k = 0, cnt = 0;     cin >> n;     cin >> x[0] >> y[0];     d = x[0];     k = y[0];     for (i = 1; i <= n; i++) {       cin >> x[i] >> y[i];       if (y[i] > y[i - 1]) {         k = y[i];       }     }     cnt = (n - 4) / 2;     cout << cnt;     return 0;   }   