Problem:
Score : 200 points

Problem Statement

There are N balls placed in a row.
AtCoDeer the deer is painting each of these in one of the K colors of his paint cans.
For aesthetic reasons, any two adjacent balls must be painted in different colors.

Find the number of the possible ways to paint the balls.

Constraints

1≦N≦1000

2≦K≦1000

The correct answer is at most 2^{31}-1.

Input

The input is given from Standard Input in the following format:

N K

Output

Print the number of the possible ways to paint the balls.

Sample Input 1

2 2

Sample Output 1

2

We will denote the colors by 0 and 1. There are two possible ways: we can either paint the left ball in color 0 and the right ball in color 1, or paint the left in color 1 and the right in color 0.

Sample Input 2

1 10

Sample Output 2

10

Since there is only one ball, we can use any of the ten colors to paint it. Thus, the answer is ten.

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

use std::io;

fn read_lines() -> (i32, i32) {
    let mut line = String::new();
    io::stdin().read_line(&mut line).unwrap();
    let input: Vec<i32> = line.split_whitespace().map(|x| x.trim().parse::<i32>().unwrap()).collect();
    return (input[0], input[1]);
 }

fn calcu_alignment(n: i32, k: i32) -> u32 {
    let mut res: u32 = k as u32;
    for _ in 1..n {
        res *= (k-1) as u32;
    }
    return res;
}

fn main() {
    let (n, k) = read_lines();
    println!("{}", calcu_alignment(n, k));
}