func_code_string: #include <bits/stdc++.h>   using namespace std;   long long n, k, res, ans[1010101];   queue<long long> q;   stack<long long> st;   int32_t main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     cin >> n >> k;     for (long long i = 1; i <= n; ++i) {       st.push(i);       q.push(i);       k -= i;       res += i;     }     if (k < 0) {       cout << -1;       return 0;     }     while (!st.empty() && !q.empty()) {       long long vt1 = st.top(), vt2 = q.front();       if (vt2 > vt1) break;       if (k < vt1 - vt2) {         st.pop();         ans[vt1] = vt1;       } else {         ans[vt1] = vt2;         ans[vt2] = vt1;         k -= vt1 - vt2;         res += vt1 - vt2;         st.pop();         q.pop();       }     }     cout << res <<   n ;     for (long long i = 1; i <= n; ++i) cout << ans[i] <<    ;     cout <<   n ;     for (long long i = 1; i <= n; ++i) cout << i <<    ;   }   