Problem:
Score : 100 points

Problem Statement

Cat Snuke is learning to write characters.
Today, he practiced writing digits 1 and 9, but he did it the other way around.

You are given a three-digit integer n written by Snuke.
Print the integer obtained by replacing each digit 1 with 9 and each digit 9 with 1 in n.

Constraints

111 \leq n \leq 999

n is an integer consisting of digits 1 and 9.

Input

Input is given from Standard Input in the following format:

n

Output

Print the integer obtained by replacing each occurrence of 1 with 9 and each occurrence of 9 with 1 in n.

Sample Input 1

119

Sample Output 1

991

Replace the 9 in the ones place with 1, the 1 in the tens place with 9 and the 1 in the hundreds place with 9. The answer is 991.

Sample Input 2

999

Sample Output 2

111

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

use std::io::{ stdin, stdout, Read, Write };

const N: usize = 4;

fn main() {
  let mut buf = [0; N];

  let mut stdin = stdin();
  stdin.read(&mut buf).unwrap();

  let mut i = 0;
  while i < N - 1 {
    buf[i] = if buf[i] == b'1' { b'9' } else { b'1' };
    i += 1;
  }

  let stdout = stdout();
  let mut writer = stdout.lock();
  writer.write(&buf).unwrap();
  writer.flush().unwrap();
}