#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using mint = atcoder::modint998244353;
// using mint = double;

#define rep(i, l, r) for (int i = (int)(l); i<(int)(r); i++)
#define ll long long
#define ld long double
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define siz(x) (int)(x).size()

template<class T> bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }

const int inf = 1e9;
const ll INF = 4e18;

template<class T> using pq = priority_queue<T, vector<T>, less<T>>;
template<class T> using spq = priority_queue<T, vector<T>, greater<T>>;

vector<int> di = {0, 0, 1, -1};
vector<int> dj = {1, -1, 0, 0};

struct Edge {
    int to, cost;
};

void solve() {
    int N, X, Q; cin >> N >> X >> Q;
    int ans = 0;
    rep(i, 0, Q) {
        int m; cin >> m;
        bool flg = false;
        map<int, int> cnt;
        rep(j, 0, m) {
            int f; cin >> f;
            if (f == X) {
                flg = true;
            }
            cnt[f]++;
        }
        if (flg) {
            ans += 2;
        }
        else {
            bool glg = false;
            for (auto[k, v] : cnt) if (v >= 2) glg = true;
            ans += glg;
        }
        // cout << ans << endl;
    }
    cout << (double)ans/2 << endl;
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int T = 1;
    // cin >> T;
    while(T--) {
        solve();
    }
}