#include <bits/stdc++.h>
using namespace std;
const int N = 1000;
int n;
char number[N];
int main() {
  scanf("%d", &n);
  scanf("%s", number);
  int pos = 0;
  if (n % 2 == 1) {
    printf("%c%c%c", number[0], number[1], number[2]);
    pos = 3;
  }
  for (int i = pos; i < n; i += 2) {
    if (i != 0) printf("-");
    printf("%c%c", number[i], number[i + 1]);
  }
  printf("\n");
  return 0;
}
