#include <bits/stdc++.h>
const int SIZE = 1e5 + 5;
using namespace std;
int arr[SIZE];
int com[SIZE];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL), cout.tie(NULL);
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> arr[i], com[arr[i]]++;
  vector<int> emp;
  for (int i = 1; i < n + 1; i++)
    if (com[i] == 0) emp.push_back(i);
  int k = 0;
  for (int i = 0; i < n; i++) {
    if (com[arr[i]] > 1 || arr[i] > n) com[arr[i]]--, arr[i] = emp[k++];
  }
  for (int i = 0; i < n; i++) cout << arr[i] << ' ';
}
