func_code_string: #include <bits/stdc++.h>   using namespace std;   const double eps = 1e-10;   const int inf = 1000000009;   int i, j, k, m, n, l;   int ans;   int f(int n, int m) {     return n < m ? (n + (n % 2) * (m - 1)) / 2 : f(n - m, 2 * m);   }   int main() {     cin >> n;     cout << (n < 2 ? 0 : f(n - 2, 2)) << endl;     return 0;   }   