#include<bits/stdc++.h>
using namespace std;
int main(){
  	int n;cin>>n;
  	for(int i=1;i<=n;i++){
      	cout<<(i+1)/2<<" "<<(n+i+1)/2<<endl;
    }
}
#include <cstdio>
int main(){
	int n;
	scanf("%d",&n);
	for(int i=1;i<=n;i++){
		printf("%d %d\n",(i<<1)%n+1,(i<<1|1)%n+1);
	}
	return 0;
}
