#include<cstdio>
#include<iostream>
#include<algorithm>
#include<string>
#include<vector>

using namespace std;

typedef vector<int> VI;
typedef long long LL;

#define FOR(x, b, e) for(int x=b; x<=(e); ++x)
#define FORD(x, b, e) for(int x=b; x>=(e); --x)
#define REP(x, n) for(int x=0; x<(n); ++x)
#define VAR(v, n) __typeof(n) v = (n)
#define ALL(c) (c).begin(), (c).end()
#define SIZE(x) ((int)(x).size())
#define FOREACH(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define PB push_back
#define ST first
#define ND second

bool isValid(int ones, int n) {
    return ones >= 3 * n && ones <= 6 * n;
}

int main() {
	ios_base::sync_with_stdio(0);
    int n;
    string bytes;
    cin >> n >> bytes;
    int ones = 0;
    for(char c:bytes) if(c == '1') ones++;
    if(!isValid(ones, n)) {
        cout << "NIE\n";
        return 0;
    }
    int current = 3;
    vector<char> letters = { 'a', 'c', 'g', 'o' };
    while(n > 0) {
        if(isValid(ones - current, n - 1)) {
            cout << letters[current - 3];
            ones -= current;
            n--;
        } else current++;
    }
    cout << '\n';

    return 0;
}