#include <bits/stdc++.h>
using namespace std;
int main() {
  int ks = 1, tt, i, j, k, n;
  char a[104];
  while (scanf("%d", &n) == 1) {
    scanf("%s", a);
    k = n / 2;
    tt = k * 2;
    for (i = 0; i < tt; i += 2) {
      if (i) printf("-");
      printf("%c%c", a[i], a[i + 1]);
    }
    if (n & 1) cout << a[n - 1];
    cout << endl;
  }
  return 0;
}
