#include <bits/stdc++.h>
#define int long long 
using namespace std;


signed main() {
string S;
cin >> S;
reverse(S.begin(), S.end());

string ans = "";
for( int i = 0; i < S.size(); i++ ){
if( i % 3 == 0 && i != 0 ) ans = "," + ans;
ans = S.at(i) + ans;
}

cout << ans << endl;

}