#include<fstream.h> //doar t 8+ 4 tle si 5 wa :|
#include<iomanip.h>
#define dim 50001
int v[2][dim];
int main()
{ifstream f("secv3.in");
 ofstream g("secv3.out");
 int n,l,i,j,n1,n2,u;
 long double max=-2000000000,man1,man2,man;
 f>>n>>l>>u;
 n1=(n-l)+1;
 for(i=1;i<=n;i++)
  {f>>v[0][i];
   v[0][i]=v[0][i]+v[0][i-1];
  }
 for(i=1;i<=n;i++)
  {f>>v[1][i];
   v[1][i]=v[1][i]+v[1][i-1];
  }
/* for(i=1;i<=n1;i++)//nu de la 0
  {n2=i+u-1;//+(-1)
   if(n2>n) n2=n;
   for(j=(i+l-1);(j<=n2);j++)//nu de la i+l;
    {man1=v[0][j]-v[0][i];
     man2=v[1][j]-v[1][i];
     if(man2)
      {man=man1/man2;
       if(man>max)
       max=man;
      }
    }
  }
*/
 for(i=1;i<=n;i++)
  {n1=i-u;
   n2=i-l;
   for(j=n1;j<=n2;j++)
    if(j>=0.0)
     {man1=v[0][i]-v[0][j];
      man2=v[1][i]-v[1][j];
      if(man2)
       {man=man1/man2;
	if(man>max)
	max=man;
       }
     }
  }
f.close();
 g<<setprecision(2)<<max<<'\n';
g.close();
return 0;
}