import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 * Created by Rose on 10/18/2016.
 */
public class CuttingPaperSquares {
    public static void main(String args[]) throws IOException {
        long n, k, m, f = 0;
        long bCharged, bActual;
        long sum = 0;
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String input[] = br.readLine().split(" ");
        n = Long.parseLong((input[0]));
        m = Long.parseLong((input[1]));
        sum+=(m*(n-1));
        sum+=(m-1);
        System.out.println(sum);

    }
}