#include<iostream> using namespace std; int f(int k) { if(k==4){ cout<<"4,5-->9,10\n"; cout<<"8,9-->4,5\n"; cout<<"2,3-->8,9\n"; cout<<"7,8-->2,3\n"; cout<<"1,2-->7,8\n";} else { cout<<k<<","<<k+1<<"-->"<<2*k+1<<","<<2*k+2<<endl; cout<<2*k-1<<","<<2*k<<"-->"<<k<<","<<k+1<<endl; f(k-1);} } int main(){ int n; cin>>n; f(n); return 0; }