func_code_string: #include <bits/stdc++.h>   using namespace std;   long long n, k, ar[1000005], br[1000005];   int main() {     scanf( %lld %lld , &n, &k);     long long min_ = 0, max_ = 0;     for (int i = 1; i < n + 1; i++) {       ar[i] = br[i] = i;       min_ += i;       max_ += max((long long)i, n - i + 1);     }     if (k < min_) {       cout <<  -1 ;       return 0;     } else {       long long tot = min_;       long long t = n - 1;       k -= min_;       for (int i = 1; i < n + 1; i++) {         if (i >= n + 1 - i) break;         if (k > t) {           tot += t;           min_ += t;           swap(br[i], br[n + 1 - i]);         } else {           tot += k;           min_ += k;           swap(br[i], br[i + k]);           break;         }         k -= t;         t -= 2;       }       cout << tot <<   n ;     }     for (int i = 1; i < n + 1; i++) cout << ar[i] <<    ;     cout <<   n ;     for (int i = 1; i < n + 1; i++) cout << br[i] <<    ;     cout <<   n ;   }   