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: Wrong Answer)

use std::io;

fn main() {
    let mut S = String::new();
    let mut K = String::new();
    io::stdin().read_line(&mut K);
    io::stdin().read_line(&mut S);
    let k : usize = K.trim().parse().unwrap();
    let mut n :usize = 0;
    if S.len() <= k {
        println!("{}",S)
    }else{
        n = S.len() - k;
        for i in 0..n {
            S.pop();
        }
        println!("{}...",S);
    }

}