func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(0);     cin.tie(NULL);     cout.tie(NULL);     long long n, l = 1, r;     cin >> n;     r = n;     if (n == 1) {       cout << 1 << endl << 1;       return 0;     }     if (n == 2) {       cout << 1 << endl << 1;       return 0;     }     if (n == 3) {       cout << 2 << endl << 1 <<     << 3;       return 0;     }     if (n == 4) {       cout << 4 << endl << 2 <<     << 4 <<     << 1 <<     << 3;       return 0;     }     if (n == 5) {       cout << 5 << endl << 1 <<     << 3 <<     << 5 <<     << 2 <<     << 4;       return 0;     }     vector<long long> a(n + 1);     long long f = 0;     for (long long i = 1; i <= n; i++) {       if (f) {         a[l] = i;         l++;       } else {         a[r] = i;         r--;       }       f += 1;       f %= 2;     }     for (long long i = 1; i < n; i++) {       if (abs(a[i] - a[i + 1]) == 1) {         swap(a[i + 1], a[n]);       }     }     cout << n <<   n ;     ;     for (long long i = 1; i <= n; i++) {       cout << a[i] <<    ;     }   }   