#include<bits/stdc++.h>
using namespace std;
int a,b,c;
double n;
int M(double a,double b,double c)
{
	return max(max(a,b),c);
}
int main(){
	scanf("%d%d%d",&a,&b,&c);
	printf("%.3lf",M(a,b,c)/(M(a+b,b,c)+M(a,b,b+c)));
}

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