Given an array $a$ of length $n$, find another array, $b$, of length $n$ such that:

• for each $i$ $(1 \le i \le n)$ $MEX(\{b_1$, $b_2$, $\ldots$, $b_i\})=a_i$.

The $MEX$ of a set of integers is the smallest non-negative integer that doesn't belong to this set.

If such array doesn't exist, determine this.

The first line contains an integer $n$ ($1 \le n \le 10^5$) — the length of the array $a$.

The second line contains $n$ integers $a_1$, $a_2$, $\ldots$, $a_n$ ($0 \le a_i \le i$) — the elements of the array $a$. It's guaranteed that $a_i \le a_{i+1}$ for $1\le i < n$.

If there's no such array, print a single line containing $-1$.

Otherwise, print a single line containing $n$ integers $b_1$, $b_2$, $\ldots$, $b_n$ ($0 \le b_i \le 10^6$)

If there are multiple answers, print any.