#include <stdio.h>
int max3(int a,int b,int c);
int main() {
   int a,b,c;
   scanf("%d %d %d",&a,&b,&c);
   float m=1.0*max3(a+b,b,c)/(max3(a,b+c,c)+max3(a,b,b+c));
   printf("%.2f\n",m);
   return 0;
} 

int max3(int a,int b,int c){
    int max;
   int arr[3];
   arr[0]=a;
   arr[1]=b;
   arr[2]=c;
   max=arr[0];
   for(int i=0;i<3;i++){
    if(arr[i]>max){
        max=arr[i];
    }
   }
    return max;
}