#include<bits/stdc++.h>
using namespace std;
void m(double a,double b,double c){
	double ans=max({a,b,c})/(max({a+b,b,c})*max({a,b,b+c}));
	printf("%.3lf",ans);
}
int main(){
	int a,b,c;
	cin>>a>>b>>c;
	m(a,b,c);
	return 0;
}