#include <bits/stdc++.h>
using namespace std;
int main() {
  char ph[100];
  int i, j, k, t;
  while (cin >> t) {
    if (t % 2 == 0)
      for (i = 1; i <= t; i++) {
        cin >> ph[i];
        cout << ph[i];
        if (i % 2 == 0 && i < t) cout << "-";
        if (i == t) cout << endl;
      }
    if (t % 2 != 0) {
      for (j = 1; j <= t / 2; j++) {
        cin >> ph[j];
        cout << ph[j];
        if (j % 2 == 0 && j < t / 2) cout << "-";
      }
      for (k = t / 2 + 1; k <= t; k++) {
        cin >> ph[j];
        cout << ph[j];
        if ((k + 1) % 2 == 0 && k < t) cout << "-";
        if (k == t) cout << endl;
      }
    }
  }
}
