#include <iostream>
using namespace std;

char tab[] = { 'a', 'c', 'g', 'o'}; //3, 4, 5, 6

void task(int n, int k) {
    if (3 * n > k || 6 * n < k) {
        cout << "NIE";
        return;
    }
    k -= n * 3;
    int w = 0;
    while (w < n) {
        for (int i = 3; i >= 0; i--) {
            if (k >= i) {
                k -= i;
                cout << tab[i];
                w++;
                break;
            }
        }
    }
    return;
}

int main()
{
    int n;
    char a;
    int k = 0;
    cin >> n;
    for (int i = 0; i < 8 * n; i++) {
        cin >> a;
        k += a - '0';
    }
    task(n, k);
}