#include <bits/stdc++.h>
using namespace std;
int b[100010];
vector<int> c;
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    int a;
    cin >> a;
    b[a] += 1;
    c.push_back(a);
  }
  int p = 1;
  for (int i = 0; i < n; i++) {
    if (b[c[i]] > 1 || c[i] > n) {
      while (b[p] > 0) p++;
      b[c[i]]--;
      c[i] = p;
      p++;
    }
  }
  for (int i = 0; i < n; i++) {
    if (i != n - 1)
      cout << c[i] << " ";
    else
      cout << c[i] << endl;
  }
}
