#include<bits/stdc++.h>
using namespace std;
#define ALL(x) x.begin(),x.end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(x) cout<<#x<<":";cout<<x<<endl;
#define debugs(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define INF 1000000000
#define mod 1000000007
using ll=long long;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

signed main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    string s;cin>>s;
    reverse(ALL(s));
    string ans="";
    ans.push_back(s[0]);
    for(int i=1;i+1<s.size();i++){
        if(i%3==0) ans.push_back(',');
        ans.push_back(s[i]);
    }
    ans.push_back(s.back());
    reverse(ALL(ans));
    cout<<ans<<endl;
    return 0;
}