#include <stdio.h>
#include "math.h"
int main()
{
    int a,b,c;
    scanf("%d%d%d",&a,&b,&c);
    double m;
    m=(double)fmax(fmax(a+b,c),c)/(fmax(a,fmax(b+c,c))+fmax(a,fmax(b,b+c)));
   printf("%.2f",m);
    return 0;
}