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