#include <bits/stdc++.h>
using namespace std;
int n;
int main() {
  cin >> n;
  string s;
  cin >> s;
  while (s.size()) {
    if (s.size() >= 4 || s.size() == 2) {
      cout << s[0] << s[1];
      s.erase(s.begin());
      s.erase(s.begin());
      if (!s.size()) break;
    } else {
      cout << s[0] << s[1] << s[2];
      break;
    }
    cout << "-";
  }
  puts("");
  return 0;
}
