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.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.PriorityQueue;
import java.util.StringTokenizer;
import java.util.TreeSet;


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[] arr = new int[n];

    int[] dp = new int[n];

    for (int i = 0; i < n; ++i) {
      arr[i] = sc.nextInt();
    }
    dp[0] = 0;
    for (int i = 1; i < n; ++i) {
      if (arr[i] == arr[i - 1]) {
        dp[i] = dp[i - 1];
      } else {
        dp[i] = i;
      }
    }


    for (int i = 0; i < m; ++i) {
      int l = sc.nextInt() - 1;
      int r = sc.nextInt() - 1;
      int x = sc.nextInt();
      if (arr[r] != x) {
        out.println(r + 1);
      } else if (dp[r] <= l) {
        out.println(-1);
      } else {
        if (dp[r] > 0) {
          out.println(dp[r] - 1 + 1);
        } else {
          out.println(-1);
        }

      }

    }

    out.close();
  }


  public static PrintWriter out;

  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;
    }

  }

}