#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, i, j, k, l = -1;
  string s;
  cin >> n >> s;
  k = n / 2, k--;
  for (i = 1; i <= k; i++) printf("%c%c-", s[l + 1], s[l + 2]), l += 2;
  cout << s[l + 1] << s[2 + l];
  if (n % 2) cout << s[3 + l] << endl;
  return 0;
}
