#include <bits/stdc++.h>
int main() {
  int n, l, i;
  char a[110];
  while (~scanf("%d%s", &n, a)) {
    int l = strlen(a);
    if (n == 1 || n == 2 || n == 3) {
      puts(a);
      continue;
    }
    if (n % 2 == 0) {
      for (int i = 0; i < n; ++i) {
        if (i % 2 == 0 && i != 0) {
          printf("-");
        }
        printf("%c", a[i]);
      }
      puts("");
    } else {
      printf("%c%c%c-", a[0], a[1], a[2]);
      int cnt = 0;
      for (int i = 3; i < n; ++i) {
        if (cnt % 2 == 0 && cnt != 0) {
          printf("-");
        }
        printf("%c", a[i]);
        ++cnt;
      }
      puts("");
    }
  }
}
