#include <bits/stdc++.h>
using namespace std;
int main() {
  map<int, bool> ahmed;
  map<int, bool> take;
  int n, j = 1;
  cin >> n;
  int arr[n];
  for (int k = 0; k < n; k++) cin >> arr[k], ahmed[arr[k]] = true;
  for (int k = 0; k < n; k++) {
    if (!take[arr[k]] && arr[k] <= n)
      cout << arr[k] << " ", take[arr[k]] = true;
    else {
      while (ahmed[j]) j++;
      cout << j << " ";
      j++;
    }
  }
}
