#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  char arr[200];
  cin >> arr;
  if (n <= 3)
    cout << arr;
  else {
    if (n % 2 == 0) {
      for (int i = 1; i <= n; i++) {
        cout << arr[i - 1];
        if (i % 2 == 0 && i != n) cout << "-";
      }
    } else {
      for (int i = 1; i <= n; i++) {
        cout << arr[i - 1];
        if (i % 2 == 0 && i != n - 1) cout << "-";
      }
    }
  }
}
