#pragma GCC optimize("O3")
#pragma GCC target("avx")
#include <bits/stdc++.h>
#define rep(i ,n) for(int i=0;i<(int)(n);++i)
#define repr(i ,n) for(int i=n;i>(int)(n);--i)
#define rep1(i ,n) for(int i=1;i<=(int)(n);++i)
#define ALL(a) a.begin(), a.end()
#define SORT(a) sort(ALL(a))
#define bit_check(bit, i) ((bit>>(i)) & 1)
#define PRINT(x) printf("%d\n",(x));
using namespace std;
typedef long long int int64;
typedef unsigned long long uint64;
template<class T> using V = vector<T>;
using I = int;
using VI = V<I>;
const int INF = 2e9;
const int64 MOD = 1e9 + 7;

template <class T> inline bool chmin(T& a, T b){if(a>b){a=b; return true;} return false;}
template <class T> inline bool chmax(T& a, T b){if(a<b){a=b; return true;} return false;}

int main(){
    int a , b; cin >> a >> b;
    double step=0.000001;
    double sum = 0;
    double i = (double)a + step;
    for( i ; i < b ; i += step){
        sum+=abs(( i - a) * ( i - b )*(step));
    }
    cout << fixed << sum << endl;
}