#include <bits/stdc++.h> using namespace std; double x,y,c; bool chk(double l) { double a = sqrt(x * x - l * l),b = sqrt(y * y - l * l); return (a + b) * c < a * b; } signed main() { while (cin >> x >> y >> c) { double l = 0,r = min(x,y); while (l <= r) { double mid = l + (r - l) / 2; if (chk(mid)) l = mid + 1e-4; else r = mid - 1e-4; } printf("%.3lf\n",l); } return 0; }