#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  long long n;
  cin >> n;
  long long a[n];
  map<long long, long long> m, ans;
  vector<long long> v;
  for (long long i = 0; i < n; i++) {
    cin >> a[i];
    if (m[a[i]] == 0 && a[i] <= n) {
      m[a[i]] = 1;
      ans[i] = a[i];
    } else {
      v.push_back(i);
    }
  }
  long long j = 0;
  for (long long i = 1; i <= n; i++) {
    if (m[i] == 0) {
      ans[v[j]] = i;
      j++;
    }
  }
  for (long long i = 0; i < n; i++) {
    cout << ans[i] << " ";
  }
  cout << "\n";
  return 0;
}
