from collections import Counter

n, x, q = map(int, input().split())

ans = 0.0
for _ in range(q):
    m = int(input())
    f = list(map(int, input().split()))
    counter = Counter(f)

    if counter[x] >= 1:
        ans += 1.0
    elif any(v >= 2 and k != x for k, v in counter.items()):
        ans += 0.5

print(ans)