# include<stdio.h> # include<iostream> # include<cmath> using namespace std; bool sushu(int x) { for(int i=2;i<=sqrt(x);i++) if(x%i==0) return false; return true; } int main(){ int i,n,cnt=0; cin>>n; for(i=2;i<=n-2;i++) { if(sushu(i)&&sushu(i+2)) { cnt++; cout<<i<<" "<<i+2<<endl; } } if(cnt==0)cout<<"No"; return 0; }