#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  vector<string> v;
  for (int i = 0; i < n; i += 2) {
    v.push_back(s.substr(i, 2));
    if (i == n - 1) {
      v[v.size() - 2] += v[v.size() - 1];
      v.pop_back();
    }
  }
  for (int i = 0; i < v.size(); i++) {
    cout << v[i];
    if (i != v.size() - 1) cout << "-";
  }
  return 0;
}
