#include <bits/stdc++.h>

using namespace std;


vector<int> tops;
vector<bool> seen;
vector<vector<int>> v;

void dfs(int x){
    if (seen[x]) return;
    seen[x] = true;
    for (int i : v[x]) dfs(i);
    tops.push_back(x);
}


int main() {
	
	int n; cin >> n;

    v.assign(n+1, {});
    seen.assign(n+1, false);
    vector<pair<int, int>> vv;


    for (int i = 1; i <= n; i++){
        int a; cin >> a;
        if (a == -1){
            vv.push_back({i, n+1});
            continue;
        }
        v[i].push_back(a);
        vv.push_back({i, a});
        
        for (pair<int, int> j : vv){
            if (j.second >= a) v[a].push_back(j.first);
        }
    }


    for (int i = 1; i <= n; i++) dfs(i);

    reverse(tops.begin(), tops.end());

    for (int i : tops) cout << i << " ";

    return 0;


}