#include <bits/stdc++.h>
using namespace std;
// #include <atcoder/modint>
// using namespace atcoder;
// using mint = modint998244353;
using ll = long long;
#define fix(x) fixed << setprecision(x)
#define rep(i, n) for(int i = 0; i < n; ++i)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
constexpr ll INFLL = (1LL << 62), MOD = 998244353;
constexpr int INF = (1 << 30);

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int x,n,q;
    cin >> n >> x >> q;
    double ans = 0;
    while(q--){
        int m;
        cin >> m;
        set<int> se;
        bool f1 = false, f2 = false;
        while(m--){
            int f;
            cin >> f;
            if(se.count(f)) f1 = true;
            if(f==x) f2 = true;
            se.insert(f);
        }
        if(f2) ans += 1;
        else if(f1) ans += 0.5;
    }
    cout << fix(12) << ans << '\n';
    return 0;
}