백준 JAVA 2163 초콜릿 자르기

package BAEKJOON;

import java.util.Scanner;

public class NO2163 {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();

        System.out.println(n*m-1);
    }
}