Problem:
Deque

For a dynamic array $A = \{a_0, a_1, ...\}$ of integers, perform a sequence of the following operations:

push($d$, $x$): Add element $x$ at the begining of $A$, if $d = 0$. Add element $x$ at the end of $A$, if $d = 1$.

randomAccess($p$): Print element $a_p$.

pop($d$): Delete the first element of $A$, if $d = 0$. Delete the last element of $A$, if $d = 1$.

$A$ is a 0-origin array and it is empty in the initial state.

Input

The input is given in the following format.

$q$
$query_1$
$query_2$
:
$query_q$

Each query $query_i$ is given by

0 $d$ $x$

or

1 $p$

or

2 $d$

where the first digits 0, 1 and 2 represent push, randomAccess and pop operations respectively.

randomAccess and pop operations will not be given for an empty array.

Output

For each randomAccess, print $a_p$ in a line.

Constraints

$1 \leq q \leq 400,000$

$0 \leq p < $ the size of $A$

$-1,000,000,000 \leq x \leq 1,000,000,000$

Sample Input 1

11
0 0 1
0 0 2
0 1 3
1 0
1 1
1 2
2 0
2 1
0 0 4
1 0
1 1

Sample Output 1

2
1
3
4
1

Solution in Rust (judge verdict: Accepted)

#[allow(dead_code)]
fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

#[allow(dead_code)]
fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}

#[allow(dead_code)]
fn read_vec2<T: std::str::FromStr>(n: u32) -> Vec<Vec<T>> {
    (0..n).map(|_| read_vec()).collect()
}

#[allow(dead_code)]
fn yn(result: bool) {
    if result {
        println!("Yes");
    } else {
        println!("No");
    }
}
use std::collections::VecDeque;
fn main() {
    let n = read::<usize>();
    let mut v = VecDeque::new();

    for _i in 0..n {
        let a = read_vec::<i64>();
        match a[0] {
            0 => {
                if a[1] == 0 {
                    v.push_front(a[2])
                } else {
                    v.push_back(a[2])
                }
            }
            1 => println!("{}", v[a[1] as usize]),
            _ => {
                if a[1] == 0 {
                    v.pop_front().unwrap();
                } else {
                    v.pop_back().unwrap();
                }
            }
        }
    }
}