#include <bits/stdc++.h>
#define ll long long
#define int ll
using namespace std;
const int N = 1e6 + 5;

int n;
vector <int> a, b, c, vis, used;
clock_t start;

void init () {}

void DFS (int u, int lim) {
	if (u >= lim) {
		
		for (int i = 1; i <= n; ++i) {
			cout << a[i] << " \n"[i == n];
		}
		exit (0);
		/*cout << clock () - start << "ms" << endl;
		exit (0);*/
	}
	for (int i = 0; i < lim; ++i) {
		if (used[i]) continue;
		if (abs (a[b[u] - 1] - c[i]) == 1) continue;
		else if (abs (a[b[u] + 1] - c[i]) == 1) continue;
		else {
			a[b[u]] = c[i], used[i] = true;
			DFS (u + 1, lim);
			a[b[u]] = -1, used[i] = false;
		}
	}
}

set<int> tmp;
void charming () {
	init ();
	cin >> n;
	a = vis = used = vector <int> (n + 5);
	
	for (int i = 1; i <= n; ++ i) {
		cin >> a[i];
	}
	
	for (int i = 1; i <= n; ++ i) tmp.insert(i);
	for (int i = 1; i <= n; ++ i) if (a[i] != -1) tmp.erase(a[i]);
	for (int i = 1; i <= n; ++ i) {
		if (tmp.size() < 100) break;
		if (a[i] != -1) continue;
		for (auto x : tmp) {
			if (abs(a[i-1] - x) != 1 && abs(a[i+1] - x) != 1) {
				a[i] = x; break;
			}
		}
		tmp.erase(a[i]);
	}
	
	a[0] = a[n + 1] = -1; 
	for (int i = 1; i <= n; ++i) {
		//a[i] = -1
		if (a[i] > 0) vis[a[i]] = 1;
		else b.emplace_back (i);
	}
	
	for (int i = 1; i <= n; ++i) {
		if (!vis[i]) c.emplace_back (i);
	}
	
	
	
	DFS (0, (int) b.size ());
	cout << -1 << endl;
}

signed main () {
	ios_base::sync_with_stdio (false);
	cin.tie (NULL);
	cout.tie (NULL);
	start = clock ();
	charming ();
	return 0;
}