num=int(input()) time=int(input()) biao=[] for i in range(num):     hhh=list(map(int,input().split()))     biao.append(hhh) res=[] for i in range(num):     if biao[i][1]<=time<=biao[i][2]:         res.append(biao[i][0]) if len(res)==0:     print('null') else:     res=sorted(res)     for i in res:         print(i)