#include <bits/stdc++.h>
using ll = long long;
template <typename T>
constexpr T MOD() { return 1000000007; }
template <typename T>
constexpr T INF() { return std::numeric_limits<T>::max() / 16; }
int main()
{
    std::string S;
    std::cin >> S;
    std::reverse(S.begin(), S.end());
    std::string ans;
    for (int i = 0; i < S.size(); i++) {
        ans.push_back(S[i]);
        if (i % 3 == 2 and i != S.size() - 1) { ans.push_back(','); }
    }
    std::reverse(ans.begin(), ans.end());
    std::cout << ans << std::endl;
    return 0;
}