#include <bits/stdc++.h>
#define int long long
#define sz(v) (int)v.size()
#define all(v) v.begin(), v.end()

using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;

bool valid(vector<int>& a, int i, int x){
    int n = a.size();
    if (i > 0 && abs(a[i - 1] - x) == 1) return false;
    if (i < n - 1 && abs(a[i + 1] - x) == 1) return false;
    return true;
}

void solve() {
    int N; cin >> N;
    vector<int> a;
    for (int i = 0; i < N; i++) {
        int v; cin >> v;
        a.push_back(v);
    }
    set<int> rem;
    for (int i = 1; i <= N; i++) {
        rem.insert(i);
    }
    for (int i = 0; i < N; i++) {
        if (a[i] != -1) rem.erase(a[i]);
    }

    int cnt = count(all(a), -1);

    for (int i = 0; i < N && cnt > 7; i++) {
        if (a[i] != -1) continue;
        for (auto x : rem) {
            if (valid(a, i, x)) {
                a[i] = x;
                rem.erase(x);
                break;
            }
            --cnt;
        }
    }

    vector<int> pos, val;

    for (int i = 0; i < N; i++) if (a[i] == -1) pos.push_back(i);
    val = vector<int>(all(rem));

    sort(all(val));

    do {
        for (int i = 0; i < val.size(); i++) {
            a[pos[i]] = val[i];
        }
        bool ok = true;
        for (int i = 0; i < val.size(); i++) {
            ok &= valid(a, pos[i], val[i]);
        }
        if (ok) {
            for (auto x : a) {
                cout << x << ' ';
            }
            cout << endl;
            return;
        }
    } while(next_permutation(all(val)));
    cout << -1 << endl;
}

signed main() {
#ifndef LOCAL
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
#endif
    int T = 1;
    // cin >> T;
    while (T--) solve();
}