#include <bits/stdc++.h>
using namespace std;
int n, m, t;
char s[105];
int main() {
  cin >> n;
  m = n / 2 - 1;
  for (int i = 1; i <= n; ++i) cin >> s[i];
  for (int i = 1; i <= n; ++i) {
    cout << s[i];
    if (m) {
      ++t;
      if (t == 2) {
        cout << "-";
        --m;
        t = 0;
      }
    }
  }
  cout << endl;
  return 0;
}
