백준 18301 Java

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

public class Q18301 {

	public static void main(String[] args) throws IOException {
		BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
		String s = bf.readLine();
		StringTokenizer st = new StringTokenizer(s);
		int n1 = Integer.parseInt(st.nextToken());
		int n2 = Integer.parseInt(st.nextToken());
		int n12 = Integer.parseInt(st.nextToken());
		
		int n = (n1+1)*(n2+1)/(n12+1)-1;
		
		System.out.println(n);

	}

}