#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string pd;
  cin >> pd;
  int v = 0;
  for (int i = 0; i < n; i++) {
    if (i == n - 2 && v == 1) {
      cout << pd[i] << pd[i + 1];
      break;
    }
    cout << pd[i];
    v++;
    if (v == 2 && i != n - 1) {
      cout << "-";
      v = 0;
    }
  }
  return 0;
}
