#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int N=2e5+5;
int n,L,R;
#define pw(x) ((x)*(x))
signed main()
{
    scanf("%d%d%d",&n,&L,&R);
    double ans=0;
    for(int i=0;i<=n;i++)
    {
        double s=(1.0*L*i+1.0*R*(n-i))/n;
        double t1=i*pw(s-L),t2=(n-i)*pw(s-R);
        ans=max(ans,t1+t2);
    }
    printf("%.2lf\n",ans/n); 
    return 0;
}