#include<bits/stdc++.h>
using namespace std;

int main(){
  int n;
  cin>>n;
  vector<pair<int,int>>ans(n+1);
  for(int i=1;i<=n;i++){
    ans[i].first=i*2%n;
    ans[i].second=(i*2+1)%n;
  }
  for(int i=1;i<=n;i++)cout<<ans[i].first+1<<' '<<ans[i].second+1<<'\n';
}
#include<iostream>
using namespace std;
int n,i;
int main(){
	cin>>n;
	for(i=1;i<=n;++i){
		cout<<((i+1)>>1)<<" "<<((i+n+1)>>1)<<endl;
	}
}