#include<bits/stdc++.h>
using namespace std;
int main(){
	int m,n,x,y;
    cin>>m>>n;
    x=m*n;
    if(m<n){
    	m=n-m+m;
	}
	else if(m>n){
		n=m-n+n;
	}
	y=n*m-x;
	cout<<y<<endl;
    return 0;
}
/**************************************************************
	Problem: 1324
	User: xiaojingxuan
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/