#include <bits/stdc++.h>
int main() {
  int n, i, m = 0;
  scanf("%d", &n);
  char a[n + 2];
  scanf("%s", a);
  printf("%c%c", a[0], a[1]);
  if (n % 2) printf("%c", a[2]), m = 1;
  for (i = 2 + m; i < n; i += 2) printf("-%c%c", a[i], a[i + 1]);
}
