func_code_string: #include <bits/stdc++.h>   using namespace std;   long long arr[200005], pos[200005];   int main() {     ios_base::sync_with_stdio(0);     cin.tie(NULL);     ;     long long n;     cin >> n;     cout << n <<    ;     if (n == 1) {       cout <<  1 ;       return 0;     }     if (n % 2) {       long long tmp = 1;       while (tmp < n) {         cout << tmp <<    ;         tmp += 2;       }       cout << n <<    ;       while (tmp > 1) {         cout << tmp - 2 <<    ;         tmp -= 2;       }       tmp = 2;       while (tmp < n - 1) {         cout << tmp <<    ;         tmp += 2;       }       cout << n - 1 <<     << n - 1 <<    ;       while (tmp > 2) {         cout << tmp - 2 <<    ;         tmp -= 2;       }     } else {       long long tmp = 2;       while (tmp < n) {         cout << tmp <<    ;         tmp += 2;       }       cout << n <<    ;       while (tmp > 2) {         cout << tmp - 2 <<    ;         tmp -= 2;       }       tmp = 1;       while (tmp < n - 1) {         cout << tmp <<    ;         tmp += 2;       }       cout << n - 1 <<     << n - 1 <<    ;       while (tmp > 1) {         cout << tmp - 2 <<    ;         tmp -= 2;       }     }     return 0;   }   