#include <bits/stdc++.h>
using namespace std;
const int maxn=1003;
int n, K, S, num[maxn], q[maxn], a[maxn][maxn], p[maxn][maxn]; 
double dp[maxn][maxn]; pair<double, int> temp[maxn];
int main()
{
	cin >> n >> K >> S;
	dp[0][S] = 1;//反着推
	for (int i = 1; i <= n; ++i)
	{
		for (int j = 1; j <= n; ++j)
		{
			cin >> a[i][j];
			num[i] += a[i][j];
		}
		cin >> q[i];
		for (int j = 1; j <= num[i]; ++j) cin>>p[i][j];
		sort(p[i] + 1, p[i] + num[i] + 1);
	}
	for (int i = 1; i <= K; ++i)
	{
		for (int j = 1; j <= n; ++j) temp[j] = { dp[i - 1][j],j }; 
		sort(temp + 1, temp + n + 1);
		for (int j = 1; j <= n; ++j)
		{
			int res = 1;
			for (int k = 1; k <= n; ++k)
			{
				double tempa = temp[k].first;int id = temp[k].second;
				for (int l = res; l < res + a[j][id]; ++l) dp[i][j] += p[j][l] * tempa;
				res += a[j][id];
			}
			dp[i][j] /= q[j];
		}
	}
	printf("%.10lf\n", dp[K][1]); 
	return 0;
}