Problem:
Score: 200 points

Problem Statement

We have a string S consisting of lowercase English letters.

If the length of S is at most K, print S without change.

If the length of S exceeds K, extract the first K characters in S, append ... to the end of them, and print the result.

Constraints

K is an integer between 1 and 100 (inclusive).

S is a string consisting of lowercase English letters.

The length of S is between 1 and 100 (inclusive).

Input

Input is given from Standard Input in the following format:

K
S

Output

Print a string as stated in Problem Statement.

Sample Input 1

7
nikoandsolstice

Sample Output 1

nikoand...

nikoandsolstice has a length of 15, which exceeds K=7.

We should extract the first 7 characters in this string, append ... to the end of them, and print the result nikoand....

Sample Input 2

40
ferelibenterhominesidquodvoluntcredunt

Sample Output 2

ferelibenterhominesidquodvoluntcredunt

The famous quote from Gaius Julius Caesar.

Solution in Rust (1.42.0) (judge verdict: Accepted)

pub struct Scanner {
	handle: std::io::Stdin,
	buffer: std::collections::VecDeque<String>
}

impl Scanner {
	pub fn new() -> Scanner {
		Scanner {
			handle: std::io::stdin(),
			buffer: std::collections::VecDeque::new()
		}
	}
	pub fn next<T: std::str::FromStr>(&mut self) -> Result<T, T::Err> {
		if self.buffer.len() == 0 {
			loop {
				let mut available = String::new();
				self.handle.read_line(&mut available).unwrap();
				self.buffer = available.split_whitespace().map(String::from).collect();
				if self.buffer.len() > 0 {
					break;
				}
			}
		}
		T::from_str(&self.buffer.pop_front().unwrap())
	}
}

fn main() {
	let mut scanner = Scanner::new();
	let k: usize = scanner.next().unwrap();
	let s: String = scanner.next().unwrap();
	let l = s.len();
	if k >= l {
		println!("{}", s);
	} else {
		println!("{}...", &s[..k]);
	}
}