# include <bits/stdc++.h> using namespace std ; int main ( ) { long double l , s1 , s2 ; cin >> l >> s2 >> s1 ; cout << fixed << setprecision ( 2 ) << ( ( 3 * s1 + s2 ) * l ) / ( s1 * ( s1 + 3 * s2 ) ) << endl ; return 0 ; }