#include <bits/stdc++.h>
using namespace std;
int q;
int getno(int x, int n, int ren[]) {
  for (int i = q; i <= n; i++) {
    if (ren[i] == 0) {
      q = i;
      return i;
    }
  }
}
int main() {
  int a[100009] = {0}, hash[100009] = {0};
  int n, i;
  cin >> n;
  for (i = 0; i < n; i++) {
    cin >> a[i];
    hash[a[i]]++;
  }
  q = 1;
  for (i = 0; i < n; i++) {
    if (hash[a[i]] > 1 || a[i] > n) {
      hash[a[i]]--;
      a[i] = getno(a[i], n, hash);
      hash[a[i]]++;
    }
  }
  for (int i = 0; i < n; i++) cout << a[i] << " ";
  return 0;
}
