#include <bits/stdc++.h>

using namespace std;

typedef int ll;

double pi = acos(-1);
const int INF = 1e9 + 7;
const ll INF64 = 1e18 + 7;

int main()
{
    int a;
  ll minimal = INF; maximal = -INF;
  cin >> a;
  vector<ll> viktor(a);
  string s;
  for (int i = 0; i < a; ++i) {
    cin >> s;
    if (s[0] == 'A') {
        s[i] = INF;
    }
    else if {
        s[i] = ll(s);
    }
  }
  for (int i = 0; i < a - 1; ++i) {
    if (viktor[i] != INF && viktor[i+1] != INF) {
      cout << "none" << "\n";
      break;
    }
    if (viktor[i] != INF && viktor[i+1] != INF){}
        if((i + 1) % 2 == 1) {
            if(viktor[i] >= viktor[i+1]) {
                cout << "none" << "\n";
            }
        }
        else {
            if(viktor[i] <= viktor[i+1]) {
                cout << "none" << "\n";
            }
        }
  }

  for (int i = 1; i < a - 1; ++i) {
    if (viktor[i] == INF) {
        if (viktor[i - 1] == INF || viktor[i + 1] == INF) {
            cout << "none" << "\n";
            break;
        }
         if ((i + 1) % 2 == 1) {}

    }
  }

    return 0;
}