#include<iostream>
#include<string>
#include<algorithm>
#include<map>
#include<set>
#include<utility>
#include<vector>
#include<cmath>
#include<cstdio>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define mp make_pair
#define it ::iterator
#define all(in) in.begin(),in.end()
const double PI=acos(-1);
const double ESP=1e-10;
using namespace std;
int main(){
  string s;
  bool han=false;
  while(cin>>s){
    if(s[s.size()-1]=='.'||s[s.size()-1]==',')s=s.substr(0,s.size()-1);
    if(s.size()>2&&s.size()<7){
      if(han==true)cout<<" ";
      han=true;
      cout<<s;
    }
  }
  cout<<endl;
}