#include <bits/stdc++.h>
#include <cstdio>
#include <string>

using namespace std;

#define INF 100000000
#define YJ 1145141919
#define INF_INT_MAX 2147483647
#define INF_LL_MAX 9223372036854775807
#define EPS 1e-10
#define MOD 1000000007
#define Pi acos(-1)
#define LL long long
#define ULL unsigned long long
#define LD long double

#define int long long

signed main()
{
    double r, d;
    cin >> r >> d;
    printf("%.10f\n", sqrt(d*d - r*r));

    return 0;
}