#include <iostream>
using namespace std;
int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n, suma=0;
	string x, odp="   acgw ";
	cin >> n;
	cin >> x;
	for(int i= 0; i<x.length(); i++)
	{
		suma = suma + (x[i] - '0');
	}
	if (suma >= 3 * n and suma <= 6 * n)
	{
		int superzmienna = suma % n;
		suma /= n;
		cout << odp[suma + superzmienna];
		n--;
		while (n--)
		{
			cout << odp[suma];
		}
	}
	else cout << "NIE";
	return 0;
}