func_code_string: #include <bits/stdc++.h>   using namespace std;   long long ar[500005 + 5];   int main() {     long long i, j, k, n;     cin >> n;     if (n <= 2)       cout << 1 << endl;     else if (n == 3)       cout << 2 << endl;     else {       long long lo = 1LL, hi = n, ans = 1LL;       while (lo <= hi) {         long long md = (lo + hi) / 2LL;         if (md * 3LL <= n) {           ans = max(ans, md);           lo = md + 1LL;         } else           hi = md - 1LL;       }       if (ans * 3 + 1 <= n) {         cout << (ans * 2) + 1 << endl;       } else         cout << ans * 2 << endl;     }     return 0;   }   