#include <iostream>
#include <algorithm>
using namespace std;
int main(){
    string str,N;
    cin >> str;
    reverse(str.begin(),str.end());
    for(int i=0;i<str.size();i++){
        N+=str[i];
        if(i%3==2 && i+1!=str.size())N+=",";
    }
    reverse(N.begin(),N.end());
    cout << N << endl;
    return 0;
}