#include <bits/stdc++.h>
using namespace std;
int n, a[100005], ap[100005];
int main() {
  cin >> n;
  int pos = 1;
  for (int i = 0; i < n; ++i) {
    cin >> a[i];
    ++ap[a[i]];
    while (ap[pos] != 0) {
      ++pos;
    }
  }
  for (int i = 0; i < n; ++i) {
    if (ap[a[i]] > 1 || a[i] > n) {
      ap[a[i]]--;
      a[i] = pos;
      ap[pos]++;
      while (ap[pos] != 0) {
        ++pos;
      }
    }
  }
  for (int i = 0; i < n; ++i) {
    cout << a[i] << " ";
  }
  return 0;
}
