#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (ll i = 0; i < (n); ++i)
#define rep1(i, n) for (ll i = 1; i < (n); ++i)
#define rrep(i, n) for (ll i = n; i > 0; --i)
#define bitrep(i, n) for (ll i = 0; i < (1 << n); ++i)
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define yesNo(b) ((b) ? "Yes" : "No")
using ll = long long;
using ull = unsigned long long;
using ld = long double;
string alphabet = "abcdefghijklmnopqrstuvwxyz";
string ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const double pi = 3.141592653589793;
int smallMOD = 998244353;
int bigMOD = 1000000007;

int main()
{
    string s;
    cin >> s;
    reverse(all(s));
    string ans = "";
    rep(i, s.size())
    {
        if (i % 3 == 0 && i != 0)
        {
            ans += ',';
        }
        ans += s[i];
    }
    reverse(all(ans));
    cout << ans << endl;
    return 0;
}