#include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ld = long double;

const double PI = 3.1415926535897932384626433832795;

const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { -1, 0, 1, 0 };

int gcd(int x, int y) { return y ? gcd(y, x % y) : abs(x); }
ll gcd(ll x, ll y) { return y ? gcd(y, x % y) : abs(x); }
int lcm(int x, int y) { return x / gcd(x, y) * y; }
ll lcm(ll x, ll y) { return x / gcd(x, y) * y; }

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	string s;
	cin >> s;
	reverse(begin(s), end(s));

	string ans = "";
	for (int i = 0; i < (int)s.size(); i++) {
		if (i % 3 == 0 && i != 0) {
			ans += ',';
			ans += s[i];
			continue;
		}

		ans += s[i];
	}
	reverse(begin(ans), end(ans));

	cout << ans << endl;
	return 0;
}