#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;
using ll = long long;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    string s;
    cin>>s;
    string ans = "";
    int cnt = 0;
    for(int i = s.size()-1;i>=0;i--){
        ans = string(1,s[i]) + ans;
        cnt++;
        if(cnt==3&&i!=0){
            cnt = 0;
            ans = "," + ans;
        }
    }
    cout<<ans<<endl;
}