#include <bits/stdc++.h>
using namespace std;
void print_decreasing_increasing(int n){
	if(n==0){
		return;
	}
	cout<<n<<endl;
	print_decreasing_increasing(n-1);
	cout<<n<<endl;
}

int main(){
	int n;
	cin>>n;
	print_decreasing_increasing(n);
}
