#include <bits/stdc++.h>
using namespace std;
bool used[100001];
int ans[100001], a[100001];
int main() {
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    if (a[i] <= n && !used[a[i]]) {
      used[a[i]] = 1;
      ans[i] = a[i];
    }
  }
  int first = 1;
  for (int i = 1; i <= n; i++) {
    if (ans[i] == 0) {
      while (used[first]) first++;
      ans[i] = first;
      first++;
    }
  }
  for (int i = 1; i <= n; i++) {
    cout << ans[i] << " ";
  }
}
