#include <bits/stdc++.h>

using namespace std;

constexpr int MIN_PER = 3, MAX_PER = 6;
char OF_PER[MAX_PER - MIN_PER + 1] = {'a', 'c', 'g', 'o'};

int main()
{
    ios::sync_with_stdio(false); cin.tie(nullptr);

    size_t n; string S;
    cin >> n >> S;

    int x = count(S.begin(), S.end(), '1');
    x -= n * MIN_PER;

    if(x < 0 or x > (MAX_PER - MIN_PER) * (int)n) {
        cout << "NIE" << endl;
        return 0;
    }

    string R(n, '?');
    for(size_t i = 0; i < n; i++) {
        int y = min(x, MAX_PER - MIN_PER);
        R[i] = OF_PER[y];
        x -= y;
    }

    cout << R << endl;
}