Persistent stack

Input

The first line contains the number of operations $n$ (1 \le n \le 200\,000). The line i + 1 describes the operation $i$:

• $tm$ — add to the top of stack number $t$ (0 \le t < i) the number (0 < m \le 1000);

• $t0$ — remove the top element from stack number $t$ (0 \le t < i). It is guaranteed that stack $t$ is not empty.

The result of operation $i$, described in line i + 1, is the creation of stack number $i$. Initially, there is an empty stack with number zero.

All input numbers are integers.

Output

For each delete operation, print the deleted element in a separate line.

Examples