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