#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  string str;
  cin >> n >> str;
  int p = 0;
  if (n % 2 == 1) {
    p = 3;
    cout << str.substr(0, 3);
    if (n != 3) cout << "-";
  }
  for (int i = p; i < str.length(); i += 2) {
    cout << str.substr(i, 2);
    if (i != str.length() - 2) cout << "-";
  }
  return 0;
}
