#include <bits/stdc++.h>
int main() {
  const int N = 128;
  int n;
  char a[N];
  scanf("%d%s", &n, a);
  int i;
  for (i = 0; i < 2 + n % 2; ++i) {
    putchar(a[i]);
  }
  for (; i < n; i += 2) {
    putchar('-');
    putchar(a[i]);
    putchar(a[i + 1]);
  }
  return 0;
}
