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