#include<cstdio>
#include<stdlib.h>
#pragma warning(disable:4996)
using namespace std;
#define MAX 100005
typedef struct node
{
int tea;
int stucount;
int* stu;
int be;
double z;
}Node;
double R = 0.0;
Node* s;
void kongfu(Node* t)
{
for (int i = 0; i < t->stucount; i++)
{
if (s[t->stu[i]].stucount == 0)
{
s[t->stu[i]].z = t->z * R * s[t->stu[i]].be;
continue;
}
s[t->stu[i]].z = t->z * R;
kongfu(&s[t->stu[i]]);
}
}
int main()
{
s = (Node*)malloc(sizeof(Node) * MAX);
int N;
double Z, r;
scanf("%d %lf %lf", &N, &Z, &r);
R = (100 - r) / 100.0;
for (int i = 0; i < N; i++)
{
scanf("%d", &s[i].stucount);
if (s[i].stucount == 0)
{
scanf("%d", &s[i].be);
continue;
}
s[i].stu = (int*)malloc(s[i].stucount * sizeof(int));
for (int j = 0; j < s[i].stucount; j++)
{
scanf("%d", &s[i].stu[j]);
}
}
s[0].z = Z;
kongfu(&s[0]);
double count = 0.0;
for (int i = 0; i < N; i++)
{
if (s[i].stucount == 0)
{
count += s[i].z;
}
}
long long count1 = count;
printf("%lld", count1);
return 0;
}