#include<bits/stdc++.h> using namespace std; int main(){ int i,j,c=0,d=0,k,n; cin>>n; for(i=2;i<=n;i++){ for(j=1;j<=i;j++){ if(i%j==0){ c++; } } for(k=1;k<=i+2;k++){ if((i+2)%k==0){ d++; } } if(c<=2&&d<=2){ cout<<i<<" "<<i+2<<endl; } c=0; d=0; } return 0; } /************************************************************** Problem: 1139 User: xuanhua Language: C++ Result: Wrong Answer ****************************************************************/