Qualifying Contest

                                                Qualifying Contest  

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Very soon Berland will hold a School Team Programming Olympiad. From each of the m Berland regions a team of two people is invited to participate in the olympiad. The qualifying contest to form teams was held and it was attended by n Berland students. There were at least two schoolboys participating from each of the m regions of Berland. The result of each of the participants of the qualifying competition is an integer score from 0 to 800 inclusive.

The team of each region is formed from two such members of the qualifying competition of the region, that none of them can be replaced by a schoolboy of the same region, not included in the team and who received a greater number of points. There may be a situation where a team of some region can not be formed uniquely, that is, there is more than one school team that meets the properties described above. In this case, the region needs to undertake an additional contest. The two teams in the region are considered to be different if there is at least one schoolboy who is included in one team and is not included in the other team. It is guaranteed that for each region at least two its representatives participated in the qualifying contest.

Your task is, given the results of the qualifying competition, to identify the team from each region, or to announce that in this region its formation requires additional contests.

Input

The first line of the input contains two integers n and m (2 ≤ n ≤ 100 000, 1 ≤ m ≤ 10 000, n ≥ 2m) — the number of participants of the qualifying contest and the number of regions in Berland.

Next n lines contain the description of the participants of the qualifying contest in the following format: Surname (a string of length from 1 to 10 characters and consisting of large and small English letters), region number (integer from 1 to m) and the number of points scored by the participant (integer from 0 to 800, inclusive).

It is guaranteed that all surnames of all the participants are distinct and at least two people participated from each of the m regions. The surnames that only differ in letter cases, should be considered distinct.

Output

Print m lines. On the i-th line print the team of the i-th region — the surnames of the two team members in an arbitrary order, or a single character "?" (without the quotes) if you need to spend further qualifying contests in the region.

Examples

Input

5 2 Ivanov 1 763 Andreev 2 800 Petrov 1 595 Sidorov 1 790 Semenov 2 503

Output

Sidorov Ivanov Andreev Semenov

Input

5 2 Ivanov 1 800 Andreev 2 763 Petrov 1 800 Sidorov 1 800 Semenov 2 503

Output

? Andreev Semenov

解题思路：（感觉自己用了很笨的方法）首先需要用结构体数组，其次用sort(三参)对结构体数组排序，最后就是根据题意取两个成绩最好的运动员了。

#include<iostream>
#include<stdio.h>
#include<algorithm>
using namespace std;
struct competitor{
    string name;
    int region;
    int score;
}stu[100005];
bool cmp(competitor a,competitor b){
    return a.region!=b.region?a.region<b.region:a.score>b.score;
}
int main(){
     int n,m;
     cin>>n>>m;
     for(int i=0;i<n;i++){
        cin>>stu[i].name>>stu[i].region>>stu[i].score;
     }
    sort(stu,stu+n,cmp);
    //
//    for(int i=0;i<n;i++){
//       cout<<stu[i].name<<stu[i].region<<stu[i].score<<endl;
//     }
    int a=0;
    for(int i=0;i<n;i++){
        if(stu[i].region!=stu[i+1].region){a=0;continue;}
        if(a==0){
                //设置a，保证地区一致的情况下只能输出一次
            if(stu[i].region==stu[i+1].region&&stu[i+1].region==stu[i+2].region){

                if(stu[i].score==stu[i+1].score&&stu[i+1].score!=stu[i+2].score)
                    {cout<<stu[i].name<<" "<<stu[i+1].name<<endl;a=1;}
                if(stu[i].score!=stu[i+1].score&&stu[i+1].score!=stu[i+2].score)
                   {cout<<stu[i].name<<" "<<stu[i+1].name<<endl;a=1;}
                if(stu[i].score==stu[i+1].score&&stu[i+1].score==stu[i+2].score)
                    {cout<<"?"<<endl;a=1;}
                if(stu[i].score!=stu[i+1].score&&stu[i+1].score==stu[i+2].score)
                    {cout<<"?"<<endl;a=1;}
                /*
                这里，因为题目要求n>2m，至少有两个人来自一个地区；所以可以不用考虑其他情况（），
                region数一致 人数>2时，共四种情况分别为：1=2=3 1!=2!=3 1!2==3 1==2!=3 ；
                region数一致 人数=2时，只有两个人，好坏都要，不分情况；
                */
            }
            if(stu[i].region==stu[i+1].region&&stu[i+1].region!=stu[i+2].region)
                 {cout<<stu[i].name<<" "<<stu[i+1].name<<endl;a=1;}
        }


    }

}