#include <bits/stdc++.h>
#define rep(i,n) for(int i=0; i<(n); i++)
using namespace std;
typedef long long ll;

int main(){
	string s; cin>>s;
	int k=s.size();
	int r=k%3;
	if(k<=3){cout << s << endl; return 0;}
	else{
		if(k%3!=0) cout << s.substr(0,r) << ",";
		for(int i=r; i<k; i+=3){
			if(i==r) cout << s.substr(i,3);
			else cout << "," << s.substr(i,3);
		}
	}
	cout << endl;
}