#include<bits/stdc++.h>
using namespace std;
ifstream f("tije.in");
ofstream g("tije.out");
int n,t,i,j;
int main () {
    f>>n;
    for(i=n-1;i>=1;--i)
    {
        for(j=n;j>=1;--j)
            for(t=1;t<=i;++t)g<<j<<" "<<j+1<<'\n';
        for (j=1;j<=i;++j) g<<1<<" "<<n+1<<'\n';
    }
    return 0;
}