#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL);
  int n;
  cin >> n;
  string s;
  cin >> s;
  int i = 0;
  if (n % 2) {
    cout << s[0] << s[1] << s[2];
    if (i != n - 3) cout << "-";
    i += 3;
  }
  while (i < n) {
    cout << s[i] << s[i + 1];
    if (i != n - 2) cout << "-";
    i += 2;
  }
  return 0;
}
