#include <bits/stdc++.h>
using namespace std;

#define pi pair<int,int>
#define BOOST ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define X first
#define Y second


const int N = 5e5 + 7;

pi dp[N];
map<int,char> v = {{3, 'a'}, {4, 'c'}, {5, 's'}, {6, 'w'}};



//czy da sie wydać x k nominałami 
bool ok(int x, int k){
    if (x == 0){
        return k == 0;
    }
    if (x < 0) return false;

    return dp[x].X <= k and k <= dp[x].Y;
}
int main(){
    BOOST;
    
    int n;
    string s;
    cin >> n >> s;
    int x = count(s.begin(), s.end(), '1');
    // int su = n + x;
    // debug(x);

    const int INF = 2e9;
    fill(dp, dp + N, make_pair(INF, -1));
    dp[0] = {0, 0};
    for (int i = 0; i <= x; i++){
        if (dp[i].X == INF) continue;
        for (int j : {3,4,5,6}){
            dp[i + j].X = min(dp[i + j].X, dp[i].X + 1);
            dp[i + j].Y = max(dp[i + j].Y, dp[i].Y + 1);
        }
    }

    int cur = x;
    string ans = "";
    for (int len = n; len; len--){
        bool hailed = false;
        for (int c : {3,4,5,6}){
            if (ok(cur - c, len - 1)){
                hailed = true;
                cur -= c;
                ans += v[c];
                break;
            }
        }
        if (!hailed){
            cout << "NIE\n";
            return 0;
        }
    }
    cout << ans << "\n";


}