#include <iostream>
#include <math.h>
using namespace std;

int main() {
    int n, MAX = 100001;
    char b[8*MAX] = {0,}, r[MAX] = {0,};
    cin >> n >> b;
    int ones = 0;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < 8; j++) {
            if (b[8*i + j] == '1') {
                ones++;
            }
        }
    }
    for (int i = 0; i < n; i++) {
        double avg = (double) ones / (n - i);
        int rounded = round(avg);
        switch (rounded) {
            case 3: r[i] = 'a'; break;
            case 4: r[i] = 'c'; break;
            case 5: r[i] = 'g'; break;
            case 6: r[i] = 'o'; break;
            default: cout << "NIE" << endl; return 0;
        }
        ones -= rounded;
    }
    cout << r << endl;
    return 0;
}