#include<bits/stdc++.h>
#define REP(i,n) for(int i=0,i##_len=(n);i<i##_len;++i)
#define rep(i,a,b) for(int i=int(a);i<int(b);++i)
using namespace std;
using ll = long long;
const int N=1e4;

int a,b; 
double f(double x){
    return fabs((x-a)*(x-b));
}
int main(){
    cin>>a>>b;
    double ans=0;
    const double dx=double(b-a)/(double)N;
    for(int k=0;k<N;++k){
        ans += f(a+k*dx)*dx;
    }
    printf("%.6f",ans);
}