爱奇艺-Mars：n = int(raw_input()) din = list() c = dict() ans = dict() for i in range(n):     k,v = raw_input().split(' ')     din.append((k,v)) for k,v in din:     if k in c.keys():         if k in ans.keys():             ans[k] = ans[k]+[v]         else:             ans[k] = [c[k]]+[v]     else:         c[k] = v if len(ans)==0:     print("YES") else:     for k in list(sorted(ans.keys())):         print(str(k)+' '+' '.join(ans[k]))