#include<bits/stdc++.h> using namespace std; int main() { double s,vman,vkuai,ac,b,abc,danwei; cin>>s>>vman>>vkuai; ac=vman; b=(vkuai-vman)/2; abc=ac+b; danwei=s/abc; ac=ac*danwei; b=b*danwei; cout<<ac/vman; return 0; }