#include <bits/stdc++.h>
using namespace std;
int marca[100001], pode[100001];
int main() {
  int n, ind, x;
  vector<int> v, disp;
  set<int> used;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> x;
    v.push_back(x);
    used.insert(x);
  }
  for (int i = 1; i <= n; i++) {
    if (used.find(i) == used.end()) disp.push_back(i);
  }
  ind = 0;
  used.clear();
  for (int i = 0; i < n; i++) {
    if (v[i] > n or used.find(v[i]) != used.end()) {
      v[i] = disp[ind];
      ind++;
    }
    used.insert(v[i]);
  }
  for (int i = 0; i < n; i++) {
    cout << v[i] << " ";
  }
  cout << endl;
  return 0;
}
