#include <bits/stdc++.h>
using namespace std;
#define ALL(x) (x).begin(), (x).end()
#define REP(i, n) for(ll i=0; i<(ll)(n); i++)
bool chmax(auto& a, auto b) { return a<b ? a=b, true : false; }
bool chmin(auto& a, auto b) { return a>b ? a=b, true : false; }
using ll=long long; const int INF=1e9+10; const ll INFL=4e18;

#ifdef DEBUG
#include "./debug.hpp"
#else
#define debug(...)
#define print_line
#endif

//----------------------------------------------------------

void solve() {
    ll N,X,Q; cin>>N>>X>>Q;

    double ans=0;
    REP(i,Q) {
        ll M; cin>>M;
        map<int,int> mp;
        bool ok=true, ok2=true;
        REP(j,M) {
            ll F; cin>>F;
            mp[F]++;
            if(F==X) ok=false;
            else if(mp[F]==2) ok2=false;
        }

        if(!ok) ans+=1;
        else if(!ok2) ans+=0.5;
    }

    cout<<ans<<endl;
}

int main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);
    cout<<fixed<<setprecision(15);
    int T=1; //cin>>T;
    while(T--) solve();
}