#include<string>
#include<iostream>
#include<algorithm>
using namespace std;
string s1, s2;
int main(){
	int n, m, a, b, c, d, ans=0;
	cin >> n >> m;
	cin >> a >> b >> c >> d;
	b -= a;
	d -= c;
	ans = max(((n*m)/2)*d+(n*m)%2*b,n*m*b);
	ans = max(ans, ((n*m)/2)*d);
	ans = max(ans, 0);
	cout<<ans;
}