#include<stdio.h>
 void printEven(int n, int current);
 void printOdd(int n, int current);
 int main(){
     int n;
     scanf("%d", &n);
     if(n < 1){
     printf("Invalid input\n");    
     }else{
          printEven(n, 1);
         printOdd(n, 1);
     }
     return 0;
 }
 void printEven(int n, int current){
     if (current > n){
         return;
     }
     if(current % 2 == 0){
         printf("%d ", current);
     }
     printEven(n, current + 1);
 }print("\n");
 void printOdd(int n, int current){
     if (current > n){
         return;
     }
     if(current % 2 != 0){
         printf("%d ", current);
     }
     printOdd(n, current + 1);
 }