#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <numeric>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <utility>
#include <sstream>
#include <complex>

using namespace std;

#define FOR(i,a,b) for(long long i=(a);i<(b);i++)
#define REP(i,N) for(long long i=0;i<(N);i++)
#define ALL(s) (s).begin(),(s).end()
#define fi first
#define se second

#define PI acos(-1.0)
#define INF 1000000007

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<double, double> PD;
typedef pair<string, ll> PS;
typedef vector<ll> V;

string s;
vector<string> vs;

int main(){
	getline(cin, s);
	stringstream ss;
	string buf;
	string t;
	ss << s;
	while (ss >> buf){
		REP(i, buf.size()){
			if (buf[i] != ','&&buf[i] != '.'){
				t += buf[i];
			}
		}
		if (t.size() >= 3 && t.size() <= 6)vs.push_back(t);
		t.clear();
	}
	REP(i, vs.size()){
		if (i == vs.size() - 1)cout << vs[i] << endl;
		else cout << vs[i] << " ";
	}
}