Problem:
Score : 300 points

Problem Statement

Snuke and Raccoon have a heap of N cards. The i-th card from the top has the integer a_i written on it.

They will share these cards.
First, Snuke will take some number of cards from the top of the heap, then Raccoon will take all the remaining cards.
Here, both Snuke and Raccoon have to take at least one card.

Let the sum of the integers on Snuke's cards and Raccoon's cards be x and y, respectively.
They would like to minimize |x-y|.
Find the minimum possible value of |x-y|.

Constraints

2 \leq N \leq 2 \times 10^5

-10^{9} \leq a_i \leq 10^{9}

a_i is an integer.

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 ... a_{N}

Output

Print the answer.

Sample Input 1

6
1 2 3 4 5 6

Sample Output 1

1

If Snuke takes four cards from the top, and Raccoon takes the remaining two cards, x=10, y=11, and thus |x-y|=1. This is the minimum possible value.

Sample Input 2

2
10 -10

Sample Output 2

20

Snuke can only take one card from the top, and Raccoon can only take the remaining one card. In this case, x=10, y=-10, and thus |x-y|=20.

Solution in Rust (1.15.1) (judge verdict: Wrong Answer)

#[allow(unused_imports)]
use std::char::*;
#[allow(unused_imports)]
use std::cmp::*;
#[allow(unused_imports)]
use std::collections::*;
use std::io::*;
use std::str::FromStr;

#[allow(unused_macros)]
macro_rules! debug {($($a:expr),*) => {println!(concat!($(stringify!($a), " = {:?}, "),*), $($a),*);}}
#[allow(unused_macros)]
macro_rules! input {(source=$s:expr,$($r:tt)*) => {let mut iter=$s.split_whitespace(); let mut next=||{iter.next().unwrap()}; input_inner! {next,$($r)*}};($($r:tt)*) => {let stdin=std::io::stdin();let mut bytes=std::io::Read::bytes(std::io::BufReader::new(stdin.lock())); let mut next=move||->String{bytes.by_ref().map(|r|r.unwrap() as char).skip_while(|c|c.is_whitespace()).take_while(|c|!c.is_whitespace()).collect()}; input_inner! {next,$($r)*}};}
#[allow(unused_macros)]
macro_rules! input_inner {($next:expr) => {}; ($next:expr,) => {}; ($next:expr,$var:ident:$t:tt$($r:tt)*) => {let $var=read_value!($next,$t); input_inner! {$next$($r)*}};}
#[allow(unused_macros)]
macro_rules! read_value {($next:expr,($($t:tt),*)) => {($(read_value! ($next,$t)),*)}; ($next:expr, [$t:tt; $len:expr]) => {(0..$len).map(|_|read_value! ($next,$t)).collect::<Vec<_>>()}; ($next:expr,chars) => {read_value! ($next,String).chars().collect::<Vec<char>>()}; ($next:expr,usize1) => {read_value! ($next,usize)-1}; ($next:expr,$t:ty) => {$next().parse::<$t>().expect("Parse error")};}

#[derive(PartialEq, PartialOrd)]
pub struct Total<T>(pub T);
impl<T: PartialEq> Eq for Total<T> {}
impl<T: PartialOrd> Ord for Total<T> {
    fn cmp(&self, other: &Total<T>) -> std::cmp::Ordering {
        self.0.partial_cmp(&other.0).unwrap()
    }
}

#[allow(dead_code)]
const MAX: usize = 100006;
#[allow(dead_code)]
const INF_U32: u32 = 1 << 31;
#[allow(dead_code)]
const INF_I32: i32 = 1 << 30;
#[allow(dead_code)]
const INF_U64: u64 = 1 << 63;
#[allow(dead_code)]
const INF_I64: i64 = 1 << 62;
#[allow(dead_code)]
const MOD: i64 = 1e9 as i64 + 7;

#[allow(dead_code)]
fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let stdin = stdin.lock();
    let token: String = stdin
        .bytes()
        .map(|c| c.expect("failed to read char") as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().expect("failed to parse token")
}

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

#[allow(unused_imports)]
use std::f64;


fn main() {
    input!{n:usize, a:[i64;n]};
    let mut a = a;
    a.sort();
    let mut x = 0i64;
    let mut y = a.iter().sum::<i64>();
    let mut ans = a.iter().map(|&x| x.abs()).sum::<i64>();
    for i in 0..n-1 {
        x += a[i];
        y -= a[i];
        ans = min(ans, (x-y).abs());
        //debug!(ans, x, y);
    }
    println!("{}", ans);
}