#include <bits/stdc++.h>
int main () {
    int a, b;
    scanf("%d%d", &a, &b);
    long double ans = 0;
    int k = 1000000;
    long double d = (long double)(b-a) / k;
    for (int i = 0; i < k; i++) {
        long double x = a+d*i, y = (x-a)*(x-b);
        if (y < 0) {
            ans += (-y)*d;
        }
    }
    printf("%.6Lf\n", ans);
}