Problem:
Score : 200 points

Problem Statement

Katsusando loves omelette rice.

Besides, he loves crème brûlée, tenderloin steak and so on, and believes that these foods are all loved by everyone.

To prove that hypothesis, he conducted a survey on M kinds of foods and asked N people whether they like these foods or not.

The i-th person answered that he/she only likes the A_{i1}-th, A_{i2}-th, ..., A_{iK_i}-th food.

Find the number of the foods liked by all the N people.

Constraints

All values in input are integers.

1 \leq N, M \leq 30

1 \leq K_i \leq M

1 \leq A_{ij} \leq M

For each i (1 \leq i \leq N), A_{i1}, A_{i2}, ..., A_{iK_i} are distinct.

Constraints

Input is given from Standard Input in the following format:

N M
K_1 A_{11} A_{12} ... A_{1K_1}
K_2 A_{21} A_{22} ... A_{2K_2}
:
K_N A_{N1} A_{N2} ... A_{NK_N}

Output

Print the number of the foods liked by all the N people.

Sample Input 1

3 4
2 1 3
3 1 2 3
2 3 2

Sample Output 1

1

As only the third food is liked by all the three people, 1 should be printed.

Sample Input 2

5 5
4 2 3 4 5
4 1 3 4 5
4 1 2 4 5
4 1 2 3 5
4 1 2 3 4

Sample Output 2

0

Katsusando's hypothesis turned out to be wrong.

Sample Input 3

1 30
3 5 10 30

Sample Output 3

3

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#define _CRT_SECURE_NO_WARNINGS
#include "bits/stdc++.h"
#if defined(_MSC_VER) || defined(ONLINE_JUDGE)
#define getchar_unlocked _getchar_nolock
#define putchar_unlocked _putchar_nolock
#endif
using namespace std;
#define rep(i, n) for(int i=0; i<(n); ++i)
#define FOR(i, m, n) for(int i=(m); i<(n); ++i)
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(),(x).end()
#define mp make_pair
#define pb push_back
#define dump(x) cerr<<#x<<" = "<<(x)<<endl;
using LL=long long;
using VI=vector<int>;     using VL=vector<LL>;
using VVI=vector<VI>;     using VVL=vector<VL>;
using PII=pair<int, int>; using PLL=pair<LL, LL>;
using VS=vector<string>;
const int inf = (int)1e9;
const LL MOD = 1000000007;
const double pi = acos(-1.0);
const string Snum = "0123456789";
const int dx[] = { -1,0,1,0,-1,-1,1,1 }, dy[] = { 0,1,0,-1,-1,1,-1,1 };
template<class T>void Sort(T& a) { sort(a.begin(), a.end()); }
template<class T>void ReSort(T& a) { sort(a.rbegin(), a.rend()); }
template<class T>void Reverse(T& a) { reverse(a.begin(), a.end()); }
template<class T>void Unique(T& a) { a.erase(unique(a.begin(), a.end()), a.end()); }
template<class T>auto Max(const T& a) { return *max_element(a.begin(), a.end()); }
template<class T>auto Min(const T& a) { return *min_element(a.begin(), a.end()); }
template<class T, class U>int Count(const T& a, U c) { return count(a.begin(), a.end(), c); }
template<class T, class U>U Sum(const T& a, U init = 0) { return accumulate(a.begin(), a.end(), init); }
template<class T>T Age(T a, T b) { return (a + b - 1) / b; }
template<class T>T gcd(T n, T m) { return m == 0 ? n : gcd(m, n % m); }
template<class T>T lcm(T n, T m) { return n / gcd(n, m) * m; }

string InputStringFast() {
	string ret; char c = getchar_unlocked();
	while (c != '\0' && c != '\n' && c != '\t' && c != ' ') { ret.push_back(c); c = getchar_unlocked(); }
	return ret;
}
int InputIntFast() {
	int ret = 0; bool neg = false; char c = getchar_unlocked();
	if (c == '-') { neg = true; c = getchar_unlocked(); }
	while ('0' <= c && c <= '9') { ret = ret * 10 + (c - '0'); c = getchar_unlocked(); }
	return neg ? -ret : ret;
}
LL InputLLFast() {
	LL ret = 0; bool neg = false; char c = getchar_unlocked();
	if (c == '-') { neg = true; c = getchar_unlocked(); }
	while ('0' <= c && c <= '9') { ret = ret * 10LL + (LL(c) - LL('0')); c = getchar_unlocked(); }
	return neg ? -ret : ret;
}
double InputDoubleFast() {
	double ret = 0, dp = 0; bool neg = false, adp = false;
	char c = getchar_unlocked();
	if (c == '-') { neg = true; c = getchar_unlocked(); }
	while (('0' <= c && c <= '9') || c == '.') {
		if (c == '.')adp = true;
		if (adp) { dp *= 0.1; ret += (c - '0') * dp; }
		else { ret = ret * 10 + (c - '0'); }
		c = getchar_unlocked();
	}
	return neg ? -ret : ret;
}
struct InputString {
	operator string() { return InputStringFast(); }
	VS v(int n) {
		VS ret(n);
		rep(i, n)ret[i] = InputStringFast();
		return ret;
	}
}ins;
struct InputInt {
	operator int() { return InputIntFast(); }
	VI v(int n) {
		VI ret(n);
		rep(i, n)ret[i] = InputIntFast();
		return ret;
	}
	VVI vv(int h, int w) {
		VVI ret(h, VI(w));
		rep(i, h)rep(j, w)ret[i][j] = InputIntFast();
		return ret;
	}
}ini;
struct InputLL {
	operator LL() { return InputLLFast(); }
	VL v(int n) {
		VL ret(n);
		rep(i, n)ret[i] = InputLLFast();
		return ret;
	}
	VVL vv(int h, int w) {
		VVL ret(h, VL(w));
		rep(i, h)rep(j, w)ret[i][j] = InputLLFast();
		return ret;
	}
}inl;
struct InputDouble {
	operator double() { return InputDoubleFast(); }
	vector<double> v(int n) {
		vector<double> ret(n);
		rep(i, n)ret[i] = InputDoubleFast();
		return ret;
	}
}ind;

int main() {
	int n = ini, m = ini;
	VI cnt(m);
	rep(i, n) {
		int k = ini;
		rep(i, k)cnt[ini - 1]++;
	}
	cout << Count(cnt, n) << endl;
}