int Nprint(int n)
{ unsigned int i = 1; unsigned int N = n - 1; while (i < 2*n) { if (i <= n) std::cout << i << " "; else std::cout << N-- << " "; i++; } return 0;
}
int main()
{ int n = 0; std::cout << ""; std:: cin >> n; Nprint(n); std::cout << std::endl; return 0;
}