#include<stdio.h>

long long n, nr;

int main()
{
  freopen("lacate.in","r",stdin);
  scanf("%lld",&n);
  long long lmin, chei;
  if (n==1) {freopen("lacate.out","w",stdout);
  printf("1 1\n1\n1");}
   else {
  lmin=n*(n-1)/2;
  chei=lmin*2;
  freopen("lacate.out","w",stdout);
  printf("%lld %lld\n",lmin, chei);
  for (long long i=1; i<=n-1;i++)
   for (long long j=i+1; j<=n; j++)
     printf("%lld %lld\n",i, j);}
  return 0;
}