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

using ll = long long;

string solve(int n, int zero, int one) {
  zero -= 2*n;
  one -= 3*n;
  if (zero < 0 || one < 0) {
    return "NIE";
  }
  return string(zero / 3, 'p') + string(one / 3, 'w') + (zero % 3 == 1 ? "u" : one % 3 == 1 ? "t" : "");
}

int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  int zero = 0, one = 0;
  for (auto c : s) {
    if (c == '0') {
      zero++;
    } else {
      one++;
    }
  }
  cout << solve(n, zero, one) << endl;
}