#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  vector<int> a(n);
  bool used[100005] = {0};
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] >= 1 && a[i] <= n && !used[a[i]])
      used[a[i]] = 1;
    else
      a[i] = -1;
  }
  int x;
  for (int i = 1; i <= n; i++) {
    if (!used[i]) {
      x = i;
      break;
    }
  }
  for (int i = 0; i < n; i++) {
    if (a[i] == -1) {
      a[i] = x;
      x++;
      while (used[x]) x++;
    }
  }
  for (int p : a) cout << p << " ";
  cout << "\n";
  return 0;
}
