题解

#include<bits/stdc++.h>
#define ll long long                                                                  //防抄袭标记
#define MAXN 100005
#define maxn 1000005
#define MAXM 10000005
#define maxm 100000005
using namespace std;
int n;
int main(){
	cin>>n;
	for(int i = 1;i<=n;i++){
		if(i%2 ==1) cout<<2*((i+1)/2)<<" ";
		else  cout<<(i+1)/2*2-1<<" ";
	}
	return 0;
}