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.*;

public class C622 {

  public static void main(String[] args) throws IOException {
    BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)), true);
    String line = reader.readLine();
    String[] la = line.split(" ");
    int n = Integer.parseInt(la[0]);
    int m = Integer.parseInt(la[1]);
    String[] a = reader.readLine().split(" ");
    int[] z = new int[n];
    z[0] = -1;
    for (int i = 1; i < n; i++) {
      if (a[i].equals(a[i-1]))
        z[i] = z[i - 1];
      else
        z[i] = i - 1;
    }
    for (int i = 0; i < m; i++) {
      line = reader.readLine();
      la = line.split(" ");
      int l = Integer.parseInt(la[0]) - 1;
      int r = Integer.parseInt(la[1]) - 1;
      String x = la[2];
      if (!a[r].equals(x))
        writer.println(r + 1);
      else if (l <= z[r])
        writer.println(z[r] + 1);
      else
        writer.println("-1");
    }
  }
}