#include <iostream>

int n;
int t;
char C[] = {'\0', '\0', '\0', 'a', 'c', 'g', 'o'};

void input() {
    std::string s;
    std::cin >> n >> s;
    for (int i = 0; i < s.length(); i++) {
        if (s[i] == '1') {
            ++t;
        }
    }
}

void solve() {
    if (t < 3 * n || t > 6 * n) {
        std::cout << "NIE\n";
        return;
    }
    int m = t / n;
    int k = t - (m * n);
    for (int i = 0; i < k; i++) {
        std::cout << C[m + 1];
    }
    for (int i = 0; i < n - k; i++) {
        std::cout << C[m];
    }
    std::cout << "\n";
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(NULL);
    input();
    solve();
    return 0;
}