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)

fn solve(n: i32, k: i32) -> i32 {
    (1..n).fold(k, |m, _| m * (k - 1))
}

fn main() {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let mut iter = s.split_whitespace().map(|w| w.trim().parse().ok().unwrap());
    let n = iter.next().unwrap();
    let k = iter.next().unwrap();
    let ans = solve(n, k);
    println!("{}", ans);
}