#include<iostream>
#include<cstring>
#include<algorithm>
using namespace std;

char a[105];
int n;

int main()
{
	cin >> n;
	for (int i = 1; i <= n; i++)
	{
		cin >> a[i];
	}	
	for (int i = 1; i <= n - 2;i++)
	{
		cout << a[i];
		if (i % 2 == 0)cout << "-";
	}
	
	cout << a[n - 1] << a[n];
	
	return 0;
}