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