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