#include <cstdio>

using namespace std;

int n,i,j,k;

int main(){
freopen("tije.in","r",stdin);
freopen("tije.out","w",stdout);
scanf("%d",&n);
for (i=n-1;i>=1;--i)
    {
    for (j=n;j>=1;--j)
        for (k=1;k<=i;++k)
            printf("%d %d\n",j,j+1);
    for (k=1;k<=i;++k)
        printf("%d %d\n",n+1,1);    
    }
return 0;
}