#include<iostream>
using namespace std;
int main(){
    int n;
    cin>>n;
    for(int i = 1 ; i <= n ; i++){
       if(i%2==0){
        cout<<i<<" ";
       } 
    }
}

# 关于FA1002的题解
#include <bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin>>n;
    for(int i = 1 ; i <= n ; i++){
       if(i%2==0){
        cout<<i<<" ";
       } 
    }