func_code_string: #include <bits/stdc++.h>   using namespace std;   long long int gcd(long long int a, long long int b) {     if (a == 0)       return b;     else       return gcd(b % a, a);   }   long long int lcm(long long int a, long long int b) {     return (a * b) / gcd(a, b);   }   long long int fact(long long int n) {     if (n == 0)       return 1;     else       return n * fact(n - 1);   }   void solve(long long int t) {     long long int n, k;     cin >> n >> k;     long long int x = n / 2;     long long int rem = k - (x - 1);     if (n == 1) {       if (k == 0) {         cout <<  1 ;         return;       } else {         cout <<  -1 ;         return;       }     } else if (n == 2) {       if (k == 0) {         cout <<  -1 ;       } else {         cout << k <<     << k * 2;       }       return;     }     if (rem <= 0) {       cout <<  -1 ;       return;     }     cout << rem <<     << rem * 2 <<    ;     long long int c = 1;     for (long long int i = 1; i < x; i++) {       while (c == rem || c + 1 == rem || c == rem * 2 || c + 1 == rem * 2) {         c += 1;       }       cout << c <<     << c + 1 <<    ;       c += 2;       while (c == rem || c + 1 == rem || c == rem * 2 || c + 1 == rem * 2) {         c += 1;       }     }     if (n % 2 != 0) cout << c;   }   int main() {     cin.tie(0);     ios::sync_with_stdio(0);     cout.tie(0);     long long int T = 1;     for (long long int t = 1; t <= T; t++) {       solve(t);     }     return 0;   }   