#include <bits/stdc++.h>
using namespace std;
int n, cnt;
char phone[128];
int main() {
  scanf("%d", &n);
  scanf("%s", phone);
  cnt = 0;
  for (int i = 0; i < n; i++) {
    if (cnt == 2 and n - i >= 2) {
      printf("-");
      cnt = 0;
    }
    printf("%c", phone[i]);
    cnt++;
  }
  printf("\n");
  return 0;
}
