#include <bits/stdc++.h>
using namespace std;
int N;
int g2, g3;
char s[110];
int main(int argc, char** argv) {
  cin >> N;
  g2 = N / 2;
  g3 = 0;
  if (N % 2 == 1) g2--, g3++;
  cin >> s;
  int cur;
  if (g2)
    cur = 2;
  else
    cur = 3;
  for (int i = 0; i < strlen(s); i++) {
    if (cur == 0) {
      cout << "-";
      if (N - i == 3 && g3)
        cur = 3;
      else
        cur = 2;
    }
    cout << s[i];
    cur--;
  }
  cout << endl;
  return 0;
}
