#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, pointer = 0;
  string inp, result;
  cin >> n >> inp;
  if (n % 2) {
    result += inp.substr(0, 3);
    pointer = 3;
  }
  for (int i = pointer; i < n; i += 2) result += '-' + inp.substr(i, 2);
  if (result[0] == '-') result = result.substr(1, result.size() - 1);
  cout << result << endl;
  return 0;
}
