func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1e5 + 10, M = 1 << 20 | 10;   const int mod = 1e9 + 7;   long long n, m, sum;   int a[M];   int main() {     scanf( %lld%lld , &n, &m);     for (int i = 1; i <= n; i++) a[i] = i, sum += i;     if (sum > m) return puts( -1 ), 0;     for (int i = 1, j = n; i <= j;) {       if (sum + j - i <= m)         swap(a[i], a[j]), sum += j - i, i++, j--;       else         j--;     }     printf( %lld n , sum);     for (int i = 1; i <= n; i++) printf( %d  , i);     puts(  );     for (int i = 1; i <= n; i++) printf( %d  , a[i]);     puts(  );   }   