#include <iostream>
#include <vector>

using namespace std;
constexpr char L[5] = { 'a', 'c', 'g', 'o' };

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int n;
    string S;
    cin >> n >> S;

    int zeros = -2 * n, ones = -3 * n;
    for (auto c : S) {
        if (c == '0') zeros++;
        else ones++;
    }

    if (ones < 0 || zeros < 0) cout << "NIE";
    else {
        vector<int> R(n, ones / n);
        for (int i = 0; i < ones % n; i++) R[i]++;
        for (auto r : R) cout << L[r];
    }
    cout << '\n';
}