#include<bits/stdc++.h> using namespace std; int s(int n) { int i,c=0; for(i=2;i<=sqrt(n);i++) { if(n%i==0) c=1; break; } } int main() { int n,i; cin>>n; for(i=2;i<=n-2;i++) { if(s(i)==0&&s(i+2)==0) { cout<<i<<" "<<i+2<<endl; } } return 0; } /************************************************************** Problem: 1139 User: chenzhuo1 Language: C++ Result: Wrong Answer ****************************************************************/