#include <iostream>
using namespace std;
int k=0,set[1000]={0};
int main (){
        int collector_num,number,No,set_num=0,count=0,i,j,exist[41]={0},smallest=0;
        cin >> collector_num;
    for(;;){
                if(collector_num==0) break;
                for(i=0;i<collector_num;i++){
                        cin >> number;
                        for(j=0;j<number;j++){
                                cin >> No;
                                No = No-1;
                                exist[No] = exist[No]+1;
                        }
                }
                smallest = exist[0];
                for(i=0;i<41;i++){
                        if (exist[i]<smallest) {smallest = exist[i];}
                        exist[i] = 0;
                }
                set_num = smallest;
        cout << set_num<< endl;
        cin >> collector_num;
    }
        return 0 ;
}