#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define vec_input(v) for(auto it=v.begin();it!=v.end();it++){cin>>*it;}
#define vec_output(v) for(auto it=v.begin();it!=v.end();it++){if(it!=v.begin())cout<<" ";cout<<*it;}cout<<endl;
#define vec_debug(v) for(auto it=v.begin();it!=v.end();it++){cerr<<*it<<" ";}cerr<<endl;
#define yn(ans) cout<<(ans?"Yes":"No")<<endl
#define YN(ans) cout<<(ans?"YES":"NO")<<endl
#define umap unordered_map
#define uset unordered_set
using namespace std;
using ll = long long;
template <typename T>T digitsum(T n);
template <typename T>bool isPrime(T n);
template <typename T>vector<pair<T, T>> prime_factor(T n);
long long int intpow(long long int,long long int);
template <typename T>T intlog(T);
long long int combination(long long int,long long int);
long long int arith_sum1(long long int,long long int,long long int);
long long int arith_sum2(long long int,long long int,long long int);
long long int series_sum(long long int);

int main(){
    string s;
    cin>>s;
    reverse(all(s));
    vector<char> vec;
    rep(i,s.length()){
        vec.push_back(s[i]);
        if(i%3==2)vec.push_back(',');
    }
    reverse(all(vec));
    if(vec[0]==',')vec.erase(vec.begin());
    rep(i,vec.size()){
        cout<<vec[i];
    }
    cout<<endl;
}