# include <fstream>
using namespace std;
ifstream fin("tije.in");
ofstream fout("tije.out");
int n,m,i,j;
int main () {
    fin>>n;
    m=n;
    n--;
    while(n!=0){
        for(i=1;i<=n;i++)
            fout<<1<<" "<<m+1<<"\n";
        for(j=1;j<=m;j++)
            for(i=1;i<=n;i++)
                fout<<j+1<<" "<<j<<"\n";
        n--;
    }
    return 0;
}