1124.cpp

#include <iostream>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <map>
#include <cmath>
#include <string>
#include <sstream>
#include <iomanip>
#include <complex>
using namespace std;

#define ll long long
#define vvi vector< vector<int> >
#define All(X) X.begin(),X.end()
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define REP(i,n) for(int i=0;i<(int)(n);i++)
#define pb push_back 
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b){return a/gcd(a,b)*b;}

int data[200];
int main(){
	int n,q;
	while(1){
		cin >> n >> q;
		if(n==0&&q==0) return 0;
		REP(i,200) data[i] = 0;
		REP(i,n){
			int tmp;
			cin >> tmp;
			REP(j,tmp){
				int t2;
				cin >> t2;
				data[t2]++;
			}
		}
		int ans = 0;
		int pnum = 0;
		REP(i,200){
			if(data[i]>=q){
				if(pnum<data[i]){
					ans = i;
					pnum = data[i];
				}
			}
		}
		cout << ans << endl;
	}
	return 0;
}