#include <bits/stdc++.h>
int main() {
  int a[100100] = {0};
  int b[100100] = {0};
  int c[100100] = {0};
  int n, i, s = 1;
  scanf("%d", &n);
  for (i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
    if (b[a[i]] == 0 && a[i] <= n)
      b[a[i]] = 1;
    else
      c[i] = 1;
  }
  for (i = 1; i <= n; i++) {
    if (c[i] == 1) {
      while (b[s]) s++;
      a[i] = s;
      b[s] = 1;
    }
  }
  for (i = 1; i < n; i++) printf("%d ", a[i]);
  printf("%d", a[n]);
  return 0;
}
