#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint1000000007;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000000000000

int main() {
    
	string s;
	cin>>s;
	
	string ans= "";
	//reverse(s.begin(),s.end());
	while(s.size()>0){
		rep(i,3){
			if(s.size()==0)break;
			ans += s.back();
			s.pop_back();
		}
		if(s.size()!=0)ans += ',';
	}
	reverse(ans.begin(),ans.end());
	cout<<ans<<endl;
	
    return 0;
}