#include <bits/stdc++.h>
int main() {
  int n(0);
  scanf("%d\n", &n);
  std::string number;
  getline(std::cin, number);
  if (number.size() <= 3) {
    std::cout << number << std::endl;
  } else {
    int index(0);
    if (number.size() % 2) {
      std::cout << number.substr(0, 3);
      index = 3;
    } else {
      std::cout << number.substr(0, 2);
      index = 2;
    }
    while (index < number.size()) {
      std::cout << "-";
      std::cout << number.substr(index, 2);
      index += 2;
    }
    std::cout << std::endl;
  }
  return 0;
}
