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

#define mp       make_pair
#define pb       push_back
#define all(x)   (x).begin(),(x).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define repi(i,a,b) for(int i = (a); i < (b); i++)

using namespace std;

typedef    long long          ll;
typedef    unsigned long long ull;
typedef    vector<bool>       vb;
typedef    vector<int>        vi;
typedef    vector<vb>         vvb;
typedef    vector<vi>         vvi;
typedef    pair<int,int>      pii;

const int INF=1<<29;
const double EPS=1e-9;

const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};

int main(){
	string str;
	getline(cin, str);
	int cnt = 0;
	string tmp ="";
	bool flag =true;
	for(int i =0; i<str.length();i++){
		if(str[i]==','||str[i]==' '||str[i]=='.'){
			//cout <<cnt<<endl;
			if(cnt>=3&&cnt<=6){
				if(flag){
					cout <<tmp;
					flag =false;
				}else{
					cout <<" "<<tmp;
				}
			}
			cnt=0;
			tmp ="";
		}else{
			tmp +=str[i];
			cnt++;
		}
	}
	cout <<endl;
	return 0;
}