#include <bits/stdc++.h>
using namespace std;
const int Maxn = 1000 * 100 + 10;
int n;
int arr[Maxn];
bool Mark[Maxn];
vector<int> v;
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> arr[i];
    Mark[arr[i]] = true;
  }
  for (int i = 1; i <= n; i++)
    if (!Mark[i]) v.push_back(i);
  int p = 0;
  for (int i = 0; i < n; i++) {
    if (Mark[arr[i]] && arr[i] <= n) {
      cout << arr[i] << " ";
      Mark[arr[i]] = false;
    } else {
      cout << v[p] << " ";
      p++;
    }
  }
  return 0;
}
