Problem: You are given array a with n integers and m queries. The i-th query is given with three integers li, ri, xi.

For the i-th query find any position pi (li ≤ pi ≤ ri) so that api ≠ xi.

Input

The first line contains two integers n, m (1 ≤ n, m ≤ 2·105) — the number of elements in a and the number of queries.

The second line contains n integers ai (1 ≤ ai ≤ 106) — the elements of the array a.

Each of the next m lines contains three integers li, ri, xi (1 ≤ li ≤ ri ≤ n, 1 ≤ xi ≤ 106) — the parameters of the i-th query.

Output

Print m lines. On the i-th line print integer pi — the position of any number not equal to xi in segment [li, ri] or the value  - 1 if there is no such number.

Examples

Input

6 4
1 2 1 1 3 5
1 4 1
2 6 2
3 4 1
3 4 2


Output

2
6
-1
4

Solution (in JAVA):

Solution:
import java.util.*;
import java.io.*;
public class c {
    public static void main(String[] args) {
        
        MyScanner sc = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out));
        int n = sc.nextInt();
        int m = sc.nextInt();
        int[] ar = new int[n];
        for (int i=0;i<n;i++) {
            ar[i] = sc.nextInt();
        }
        int nextToLeft[] = new int[n];
        nextToLeft[0] = -1;
        //preprocess
        for (int i=1;i<n;i++) {
            if (ar[i] == ar[i-1])
                    nextToLeft[i] = nextToLeft[i-1];
            else
                nextToLeft[i] = i-1;
        }

        //for (int i=0;i<n;i++) {
        //    System.out.printf("%d ", nextToLeft[i]);
        //}
        //System.out.println();

        for (int i=0;i<m;i++) {
            int l = sc.nextInt() - 1;
            int r = sc.nextInt() - 1;
            int x = sc.nextInt();
            if (r==l) {
                if (ar[r] == x)
                    out.println(-1);
                else
                    out.println(1 +r);
            }
            else {
                if (ar[r] != x)
                    out.println(r + 1);
                else if (nextToLeft[r] >= l)
                    out.println(1 + nextToLeft[r]);
                else
                    out.println(-1);
            }
        }
        out.close();
    }
    public static PrintWriter out;
      
    //-----------MyScanner class for faster input----------
    public static class MyScanner {
      BufferedReader br;
      StringTokenizer st;
 
      public MyScanner() {
         br = new BufferedReader(new InputStreamReader(System.in));
      }
 
      String next() {
          while (st == null || !st.hasMoreElements()) {
              try {
                  st = new StringTokenizer(br.readLine());
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
          return st.nextToken();
      }
 
      int nextInt() {
          return Integer.parseInt(next());
      }
 
      long nextLong() {
          return Long.parseLong(next());
      }
 
      double nextDouble() {
          return Double.parseDouble(next());
      }
 
      String nextLine(){
          String str = "";
	  try {
	     str = br.readLine();
	  } catch (IOException e) {
	     e.printStackTrace();
	  }
	  return str;
      }

   }
}