#include<stdio.h>
int f[200005];
int cnt[200005];
int main()
{
	int n, x, q;
	scanf("%d %d %d", &n, &x, &q);
	int i, m;
	for (i = 0; i <= n; i++)
		cnt[i] = 0;
	int ans = 0, v;
	for (; q > 0; q--)
	{
		scanf("%d", &m);
		for (i = 0; i < m; i++)
			scanf("%d", &f[i]);
		for (i = 0; i < m; i++)
			cnt[f[i]]++;
		v = 0;
		for (i = 0; i < m; i++)
			if (cnt[f[i]] > 1)
				v = 1;
		if (cnt[x] > 0)
			v = 2;
		ans += v;
		for (i = 0; i < m; i++)
			cnt[f[i]]--;
	}
	if (ans % 2 > 0)
		printf("%d.5\n", ans / 2);
	else
		printf("%d\n", ans / 2);
	return 0;
}