C++ :

#include<iostream>
#include<fstream>
#include<algorithm>
    
using namespace std;
int main()
{
    int m,a=2;
    cin>>m;
    for(int i=1;i<=m*2-1;i++){
        if(i<=m)
        cout<<i<<" ";
        else{
            cout<<i-a<<" ";a+=2;
        }
    }
     
    return 0;
}