#include #define rep(i, a, n) for(int i = a; i < n; i++) #define repr(i, a, b) for(int i = a; i >= b; i--) #define int long long #define all(a) a.begin(), a.end() #define chmax(x, y) x = max(x, y) #define chmin(x, y) x = min(x, y) using namespace std; typedef pair P; const int mod = 1000000007; const int INF = 1e15; signed main(){ double r, d, ans; cin >> r >> d; ans = sqrt(d * d - r * r); printf("%.10f\n", ans); }