#include<iostream>
#include<atcoder/all>
#include<vector>
#include<algorithm>
#include<bits/stdc++.h>
#include<math.h>
#include <numeric>
#include <random>
#include<map>
#include<queue>
#include<deque>
#include <bitset>
#include<stack>
#include<set>
using namespace std;
using namespace atcoder;
#define int long long
using mint=modint998244353;
double pi=3.141592653589793128;
//cout << fixed << setprecision(10);
#define all(x) (x).begin(),(x).end()
#define rep(i,n) for (int i=0;i<(n);++i)
#define prep(i,n) for (int i=1;i<=(n);++i)
#define ep(i,j,n) for (int i=j+1;i<=(n);++i)
long long INF = 900000000000000;
int mod=998244353;

signed main(){
   int n,x,q;cin>>n>>x>>q;
   double ans=0.0;
   rep(i,q){
     int m;cin>>m;
     map<int,int> mp;
     int p=1;int q=1;
     rep(j,m){
       int c;cin>>c;
       if(c==x)p=0;
       else{mp[c]++;}
       if(mp[c]==2)q=0;
     }
     if(p==0){ans+=1.0;continue;}
     if(q==0)ans+=0.5;
   }
   cout<<ans;
}