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