/* -*- coding: utf-8 -*-
 *
 * 3280.cc:  No.3280 Black-Tailed Gull vs Monster - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_M = 200000;

/* typedef */

/* global variables */

int fs[MAX_M];

/* subroutines */

/* main */

int main() {
  int n, x, qn;
  scanf("%d%d%d", &n, &x, &qn);

  int sum = 0;
  while (qn--) {
    int m;
    scanf("%d", &m);
    for (int i = 0; i < m; i++) scanf("%d", fs + i);
    sort(fs, fs + m);

    bool ua = false, fa = false;
    for (int i = 0; i < m;) {
      int j = i;
      while (i < m && fs[j] == fs[i]) i++;

      if (fs[j] == x) { ua = true; break; }
      if (i - j > 1) fa = true;
    }

    if (ua) sum += 2;
    else if (fa) sum++;
  }

  printf("%.1lf\n", 0.5 * sum);
  
  return 0;
}