#include <bits/stdc++.h>
using namespace std;
int nums[100001];
int main() {
  int n, x[100001], y[100000], u = 0;
  cin >> n;
  for (int i = 0; i < n; i++) y[i] = i + 1;
  for (int i = 0; i < n; i++) {
    cin >> x[i];
    nums[x[i]]++;
    y[x[i] - 1] = 9999999;
  }
  sort(y, y + n);
  for (int i = 0; i < n; i++) {
    if (nums[x[i]] > 1 || x[i] > n) {
      nums[x[i]]--;
      x[i] = y[u++];
    }
    nums[x[i]]++;
    cout << x[i] << " ";
  }
  cout << endl;
  return 0;
}
