#include<iostream> #include<cmath> using namespace std; bool pd(int n); int main(){ int n; cin>>n; for(int i=2;i<=n-2;i++){ if(pd(i) && pd(i+2)){ cout<<i<<" "<<i+2<<endl; } } } bool pd(int n){ bool f; f=true; for(int i=2;i<=sqrt(n);i++){ if(n%i==0){ f=false; break; } } if(f==false || n==0 || n==1){ return false; } else { return true; } } /************************************************************** Problem: 1139 User: admin Language: C++ Result: Accepted Time:12 ms Memory:2072 kb ****************************************************************/