func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, j = 0;     cin >> n;     vector<int> ai(n);     if (n == 4) {       cout << 4 <<   n ;       cout << 3 <<     << 1 <<     << 4 <<     << 2 <<   n ;       return 0;     }     for (int i = 1; i <= n; i += 2) {       ai[j] = i;       j++;     }     for (int k = 2; k <= n; k += 2) {       if (abs(ai[j - 1] - k) != 1) {         ai[j] = k;         j++;       }     }     cout << j <<   n ;     for (int i = 0; i < j; i++) cout << ai[i] <<    ;     cout <<   n ;     return 0;   }   