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

static const int N = 5e5 + 10;

int nast[N], pop[N];

int main() {
    ios_base::sync_with_stdio(false);
    int n;
    cin >> n;
    for (int i = 1 ; i <= n ; ++i) {
        nast[i] = i+1;
        pop[i] = i-1;
    }

    for (int i = 0; i < n; ++i) {
        int a;
        cin >> a;
        nast[pop[a]] = nast[a];
        pop[nast[a]] = pop[a];
        if (nast[a] != n+1) {
            cout << nast[a] << "\n";
        } else {
            cout << "NIE\n";
        }
    }
}