#include <iostream>
#include <algorithm>
#include <string>

void solve() {
    std::string s;
    std::cin >> s;
    int n = s.length();

    std::reverse(s.begin(), s.end());

    std::string ans;
    for (int i = 0; i < n; ++i) {
        if (i > 0 && i % 3 == 0) ans.push_back(',');
        ans.push_back(s[i]);
    }

    std::reverse(ans.begin(), ans.end());
    std::cout << ans << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}