#include <fstream>
#pragma GCC optimize ("O3")

using namespace std;

ifstream fin  ("tije.in");
ofstream fout ("tije.out");

int n;

int main(){
    ios_base::sync_with_stdio(false);
    fin.tie(nullptr), fout.tie(nullptr);

    fin>>n;
    for(int i=1; i<=n; i++)
        fout<<i<<" "<<n+1<<"\n";

    for(int start=1; start<=n-2; start++){

        for(int i=start+1; i<=n-1; i++)
            fout<<start<<" "<<i<<"\n";

        for(int pas=1; pas<=start; pas++)
            fout<<n<<" "<<start<<"\n";

        for(int i=n-1; i>=start+1; i--){

            for(int pas=1; pas<=start; pas++)
                fout<<i<<" "<<i+1<<"\n";

            fout<<i<<" "<<start<<"\n";
        }
    }

    fout<<n-1<<" "<<n<<"\n";
    for(int pas=1; pas<=n; pas++)
        fout<<n+1<<" "<<n-1<<"\n";
    return 0;
}
/**
1 5 4 3 2

2 5 1 4 3

3 5 1 2 4

4
5 1 2 3


1 2 3 4 5
**/