Problem: 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

Note

In the first sample region teams are uniquely determined.

In the second sample the team from region 2 is uniquely determined and the team from region 1 can have three teams: "Petrov"-"Sidorov", "Ivanov"-"Sidorov", "Ivanov" -"Petrov", so it is impossible to determine a team uniquely.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;
import java.lang.*;


public class B{
    static long mod=1000000007;
    
    public static void main(String[] args) throws Exception{               
         InputReader in = new InputReader(System.in);       
        PrintWriter pw=new PrintWriter(System.out);   
    
        
            int n=in.readInt();
            int m=in.readInt();
        
        ArrayList<Pair> p[]=new ArrayList[m];
        for(int i=0;i<m;i++)
            p[i]=new ArrayList<Pair>();
        for(int i=0;i<n;i++)
        {
            String a=in.readString();
            int x=in.readInt();
            x--;
            int y=in.readInt();
            Pair c=new Pair(y,a);
            p[x].add(c);           
        }
        for(int i=0;i<m;i++)
        {
            Collections.sort(p[i]);
            if(p[i].size()>=3)
            {
                int x=p[i].get(1).a;
                int y=p[i].get(2).a;
                if(x>y)
                {
                    String a=p[i].get(0).b;
                    String b=p[i].get(1).b;
                    pw.println(a+" "+b);
                }
                else
                {
                    pw.println("?");
                }
            }
            else
            {
                String a=p[i].get(0).b;
                String b=p[i].get(1).b;
                pw.println(a+" "+b);
            }
        }
        //String a=in.readString();

        
        
           //pw.println(" ");             
        
        //}
                    
        
        pw.close();
    }
    
   
    public static BigInteger fact(int n)
    {
        BigInteger x=BigInteger.valueOf(1);
        for(int i=1;i<=n;i++)
        {
            x=x.multiply(BigInteger.valueOf(i));
        }
        return x;
    }
    /* returns nCr mod m */
       public static long comb(long n, long r, long m)
       {
           long p1 = 1, p2 = 1;
           for (long i = r + 1; i <= n; i++) {
               p1 = (p1 * i) % m;
           }
           p2 = factMod(n - r, m);
           p1 = divMod(p1, p2, m);
           return p1 % m;
       }
   /* returns a/b mod m, works only if m is prime and b divides a */
       public static long divMod(long a, long b, long m)
       {
           long c = powerMod(b, m - 2, m);
           return ((a % m) * (c % m)) % m;
       }
   /* calculates factorial(n) mod m */
       public static long factMod(long n, long m) {
           long result = 1;
           if (n <= 1)
               return 1;
           while (n != 1) {
               result = ((result * n--) % m);
           }
           return result;
       }
   /* This method takes a, b and c as inputs and returns (a ^ b) mod c */
       public static long powerMod(long a, long b, long c) {
           long result = 1;
           long temp = 1;
           long mask = 1;
           for (int i = 0; i < 64; i++) {
               mask = (i == 0) ? 1 : (mask * 2);
               temp = (i == 0) ? (a % c) : (temp * temp) % c;
               /* Check if (i + 1)th bit of power b is set */
               if ((b & mask) == mask) {
                   result = (result * temp) % c;
               }
           }
           return result;
       }
    static boolean isPrime(int number) {
        if (number <= 1) {
            return false;
        }
        if (number <= 3) {
            return true;
        }
        if (number % 2 == 0 || number % 3 == 0) {
            return false;
        }
        int i = 5;
        while (i * i <= number) {
            if (number % i == 0 || number % (i + 2) == 0) {
                return false;
            }
            i += 6;
        }
        return true;
    }
    
public static long gcd(long x,long y)
{
    if(x%y==0)
        return y;
    else
        return gcd(y,x%y);
}
    
public static int gcd(int x,int y)
{
    if(x%y==0)
        return y;
    else
        return gcd(y,x%y);
}
public static int abs(int a,int b)
{
    return (int)Math.abs(a-b);
}
public static long abs(long a,long b)
{
    return (long)Math.abs(a-b);
}
public static int max(int a,int b)
{
    if(a>b)
        return a;
    else
        return b;
}
public static int min(int a,int b)
{
    if(a>b)
        return b;
    else
        return a;
}
public static long max(long a,long b)
{
    if(a>b)
        return a;
    else
        return b;
}
public static long min(long a,long b)
{
    if(a>b)
        return b;
    else
        return a;
}

static boolean isPowerOfTwo (long v) {
    return (v & (v - 1)) == 0;
}
public static long pow(long n,long p,long m)
{
     long  result = 1;
      if(p==0)
        return 1;
    if (p==1)
        return n;
    while(p!=0)
    {
        if(p%2==1)
            result *= n;
        if(result>=m)
        result%=m;
        p >>=1;
        n*=n;
        if(n>=m)
        n%=m;
    }
    return result;
}
public static long pow(long n,long p)
{
    long  result = 1;
      if(p==0)
        return 1;
    if (p==1)
        return n;
    while(p!=0)
    {
        if(p%2==1)
            result *= n;        
        p >>=1;
        n*=n;        
    }
    return result;

}
static class Pair implements Comparable<Pair>
{
    int a;
    String b;
    Pair (int a,String b)
    {
        this.a=a;
        this.b=b;
    }

    public int compareTo(Pair o) {
        // TODO Auto-generated method stub
        if(this.a!=o.a)
        return -Integer.compare(this.a,o.a);
        else
            {
            int x=b.compareTo(o.b);
            if(x<0)
            return -1;
            else
                return 1;
            
            }
        //return 0;
    }
    public boolean equals(Object o) {
        if (o instanceof Pair) {
            Pair p = (Pair)o;
            return p.a == a && p.b == b;
        }
        return false;
    }
    public int hashCode() {
        return new Integer(a).hashCode() * 31 + new Integer(b).hashCode();
    }
}
    
static long sort(int a[],int n)
{      int b[]=new int[n];    
    return mergeSort(a,b,0,n-1);}
static long mergeSort(int a[],int b[],long left,long right)
{ long c=0;if(left<right)
 {   long mid=left+(right-left)/2;
     c= mergeSort(a,b,left,mid);
     c+=mergeSort(a,b,mid+1,right);
     c+=merge(a,b,left,mid+1,right); }    
    return c;     }
static long merge(int a[],int  b[],long left,long mid,long right)
{long c=0;int i=(int)left;int j=(int)mid; int k=(int)left;
while(i<=(int)mid-1&&j<=(int)right)
{ if(a[i]<=a[j]) {b[k++]=a[i++]; }
else    { b[k++]=a[j++];c+=mid-i;}}
while (i <= (int)mid - 1)   b[k++] = a[i++];
while (j <= (int)right) b[k++] = a[j++];
for (i=(int)left; i <= (int)right; i++)
    a[i] = b[i];  return c;  }
    
    
   static  class InputReader
    {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private SpaceCharFilter filter;

        public InputReader(InputStream stream)
        {
            this.stream = stream;
        }

        public int read()
        {
            if (numChars == -1)
                throw new InputMismatchException();
            if (curChar >= numChars)
            {
                curChar = 0;
                try
                {
                    numChars = stream.read(buf);
                } catch (IOException e)
                {
                    throw new InputMismatchException();
                }
                if (numChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public int readInt()
        {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if (c == '-')
            {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do
            {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public String readString()
        {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do
            {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }
        public double readDouble() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            double res = 0;
            while (!isSpaceChar(c) && c != '.') {
                if (c == 'e' || c == 'E')
                    return res * Math.pow(10, readInt());
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            }
            if (c == '.') {
                c = read();
                double m = 1;
                while (!isSpaceChar(c)) {
                    if (c == 'e' || c == 'E')
                        return res * Math.pow(10, readInt());
                    if (c < '0' || c > '9')
                        throw new InputMismatchException();
                    m /= 10;
                    res += (c - '0') * m;
                    c = read();
                }
            }
            return res * sgn;
        }
        public long readLong() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }
        public boolean isSpaceChar(int c)
        {
            if (filter != null)
                return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public String next()
        {
            return readString();
        }

        public interface SpaceCharFilter
        {
            public boolean isSpaceChar(int ch);
        }
    }

     static class OutputWriter
    {
        private final PrintWriter writer;

        public OutputWriter(OutputStream outputStream)
        {
            writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
        }

        public OutputWriter(Writer writer)
        {
            this.writer = new PrintWriter(writer);
        }

        public void print(Object... objects)
        {
            for (int i = 0; i < objects.length; i++)
            {
                if (i != 0)
                    writer.print(' ');
                writer.print(objects[i]);
            }
        }

        public void printLine(Object... objects)
        {
            print(objects);
            writer.println();
        }

        public void close()
        {
            writer.close();
        }

        public void flush()
        {
            writer.flush();
        }

    }
    /* USAGE

    //initialize
        InputReader in         = new InputReader(System.in);
        OutputWriter out    =    new OutputWriter(System.out);

    //read int
    int i = in.readInt();
    //read string
    String s = in.readString();
    //read int array of size N
    int[] x = IOUtils.readIntArray(in,N);
    //printline
    out.printLine("X");


    //flush output
    out.flush();

    //remember to close the
    //outputstream, at the end
    out.close();

    */
  static   class IOUtils {

        public static int[] readIntArray(InputReader in, int size) {
            int[] array = new int[size];
            for (int i = 0; i < size; i++)
                array[i] = in.readInt();
            return array;
    }
    }
//BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
    //StringBuilder sb=new StringBuilder("");
     //InputReader in = new InputReader(System.in);
  // OutputWriter out = new OutputWriter(System.out);
    //PrintWriter pw=new PrintWriter(System.out);
    //String line=br.readLine().trim();
               
    //int t=Integer.parseInt(br.readLine());
  //    while(t-->0)
      //{
      //int n=Integer.parseInt(br.readLine());
    //long n=Long.parseLong(br.readLine());
    //String l[]=br.readLine().split(" ");
  //int m=Integer.parseInt(l[0]);
    //int k=Integer.parseInt(l[1]);
    //String l[]=br.readLine().split(" ");
    //l=br.readLine().split(" ");
    /*int a[]=new int[n];
    for(int i=0;i<n;i++)
    {
        a[i]=Integer.parseInt(l[i]);
    }*/
       //System.out.println(" ");             
    
    //}
}