Problem:
﻿Score: 100 points

Problem Statement

In AtCoder city, there are five antennas standing in a straight line. They are called Antenna A, B, C, D and E from west to east, and their coordinates are a, b, c, d and e, respectively.

Two antennas can communicate directly if the distance between them is k or less, and they cannot if the distance is greater than k.

Determine if there exists a pair of antennas that cannot communicate directly.

Here, assume that the distance between two antennas at coordinates p and q (p < q) is q - p.

Constraints

a, b, c, d, e and k are integers between 0 and 123 (inclusive).

a < b < c < d < e

Input

Input is given from Standard Input in the following format:

a
b
c
d
e
k

Output

Print :( if there exists a pair of antennas that cannot communicate directly, and print Yay! if there is no such pair.

Sample Input 1

1
2
4
8
9
15

Sample Output 1

Yay!

In this case, there is no pair of antennas that cannot communicate directly, because:

the distance between A and B is 2 - 1 = 1

the distance between A and C is 4 - 1 = 3

the distance between A and D is 8 - 1 = 7

the distance between A and E is 9 - 1 = 8

the distance between B and C is 4 - 2 = 2

the distance between B and D is 8 - 2 = 6

the distance between B and E is 9 - 2 = 7

the distance between C and D is 8 - 4 = 4

the distance between C and E is 9 - 4 = 5

the distance between D and E is 9 - 8 = 1

and none of them is greater than 15. Thus, the correct output is Yay!.

Sample Input 2

15
18
26
35
36
18

Sample Output 2

:(

In this case, the distance between antennas A and D is 35 - 15 = 20 and exceeds 18, so they cannot communicate directly.
Thus, the correct output is :(.

Solution in Rust (1.15.1) (judge verdict: Accepted)

use std::io::{BufRead, StdinLock};
use std::str::FromStr;

fn read<T: FromStr>(stdin_lock: &mut StdinLock, buf: &mut Vec<u8>, delimiter: u8) -> T {
    buf.clear();
    let l = stdin_lock.read_until(delimiter, buf).unwrap();
    buf.truncate(l - 1); // remove delimiter
    let s = unsafe { std::str::from_utf8_unchecked(&buf) };
    s.parse().unwrap_or_else(|_| panic!("read"))
}

fn main() {
    let stdin = std::io::stdin();
    let mut stdin_lock = stdin.lock();
    let mut buf: Vec<u8> = Vec::new();
    let a = read(&mut stdin_lock, &mut buf, b'\n');
    let b = read(&mut stdin_lock, &mut buf, b'\n');
    let c = read(&mut stdin_lock, &mut buf, b'\n');
    let d = read(&mut stdin_lock, &mut buf, b'\n');
    let e = read(&mut stdin_lock, &mut buf, b'\n');
    let k = read(&mut stdin_lock, &mut buf, b'\n');
    println!("{}", solve(a, b, c, d, e, k));
}

fn solve(a: u8, _: u8, _: u8, _: u8, e: u8, k: u8) -> &'static str {
    if e - a <= k {
        "Yay!"
    } else {
        ":("
    }
}

#[test]
fn example1() {
    assert_eq!("Yay!", solve(1, 2, 4, 8, 9, 15))
}

#[test]
fn example2() {
    assert_eq!(":(", solve(15, 18, 26, 35, 36, 18))
}