#include<cstdio>
#include<iostream>
#include<cmath>
#define double long double
#define RI register int
#define CI const int&
using namespace std;
const int N=1005;
const double INF=1e18;
int n,H,S,p[N],k,x,T1,T2,st[N]; double P[N];
namespace Case1
{
	double f[N][10];
	inline void solve(void)
	{
		for (RI i=n,j;i>=1;--i) for (j=2;j<=H;++j)
		if (j>2) f[i][j]=1.0+f[i+1][j]*P[i]+f[i][j-1]*(1.0-P[i]);
		else f[i][j]=(1.0+f[i+1][j]*P[i]+T2*(1.0-P[i]))/P[i];
		printf("%.12Lf",f[1][H]);
	}
};
namespace Case2
{
	double f[N][10][10];
	inline void solve(void)
	{
		for (RI i=1;i<=n;++i) for (RI j=1;j<=H;++j) for (RI k=0;k<=S;++k) f[i][j][k]=INF;
		for (RI i=n,j,k,x;i>=1;--i)
		{
			if (st[i])
			{
				for (x=H;x>=2;--x)
				{
					for (j=x;j<=H;++j) for (k=0;k<=S;++k)
					{
						if (j>x) { f[i][j][k]=1.0+f[i+1][j][S]*P[i]+f[i][j-1][S]*(1.0-P[i]); continue; }
						f[i][j][k]=(1.0+f[i+1][j][S]*P[i]+T1*(1.0-P[i]))/P[i];
					}
				}
			} else
			{		
				for (j=2;j<=H;++j) for (k=0;k<=S;++k)
				{
					if (j>2) { f[i][j][k]=1.0+f[i+1][j][k]*P[i]+f[i][j-1][k]*(1.0-P[i]); continue; }
					if (k>0) f[i][j][k]=1.0+f[i+1][j][k]*P[i]+(f[i][j][k-1]+T1)*(1.0-P[i]);
					else f[i][j][k]=(1.0+f[i+1][j][k]*P[i]+T2*(1.0-P[i]))/P[i];
				}
			}
		}
		printf("%.12Lf",f[1][H][S]);
	}
};
int main()
{
	RI i; for (scanf("%d%d%d",&n,&H,&S),i=1;i<=n;++i)
	scanf("%d",&p[i]),P[i]=1.0*p[i]/100.0;
	for (scanf("%d",&k),i=1;i<=k;++i) scanf("%d",&x),st[x]=1;
	scanf("%d%d",&T1,&T2);
	if (S==0||T2<=T1) Case1::solve(); else Case2::solve();
	return 0;
}