#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i<(n); ++i)
using namespace std;
using ll=long long;
int main(){
    string s;
    cin>>s;
    int sl=s.length();
    string ans;
    rep(i,sl){
        ans+=s[i];
        if((i+1)%3==sl%3&&sl!=(i+1)){
            ans+=',';
        }
    }
    cout<<ans<<endl;
}