tj

#include<bits/stdc++.h>
using namespace std;

int main()
{
    string a;
    cin>>a;
    int siz = a.size();
    siz%=3;
    if(siz==0)
        siz+=3;
    for(int i = 0;i<siz;i++)
        cout<<a[i];
    for(int i = siz;i<a.size();i+=3)
        {
        cout<<",";
        for(int j = i;j<i+3;j++)
            cout<<a[j];
        }
}