#include <bits/stdc++.h>
#define ll long long int
#define w(t) int t;cin>>t;while(t--)
#define d double
using namespace std;
 d a, b;
d fun( d x)
{
    return (((x*x*x)/3)-((a+b)*x*x/2)+(a*b*x));
}
int main() {
    cin>>a>>b;
    d ans= fun(b)-fun(a);
    if(ans<0)
    ans=-ans;
    cout<<ans;
	
	return 0;
}