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.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

 public class Test
 {
     static PrintWriter pw = new PrintWriter(System.out);
     
     public static void main(String[] args)throws Exception
     {
         Reader.init(System.in);
         int n = Reader.nextInt();
         int m = Reader.nextInt();
         int[] ar = new int[n+1];
         int[] pre = new int[n+1];
         
         for(int i = 1 ; i<=n ; i++){
             ar[i] = Reader.nextInt();
             
             if(i == 1)pre[1] = -1;
             else if(ar[i] == ar[i-1])
                 pre[i] = pre[i-1];
             else
                 pre[i] = i-1;
                
         }
         
         for(int i = 0 ; i<m ; i++){
             int L = Reader.nextInt();
             int R = Reader.nextInt();
             int x = Reader.nextInt();
             boolean bb = false;
             
             while(L<=R){
                 if(ar[R] != x)
                 {
                     pw.println(R);
                     bb = true;
                     break;
                 }
                 else
                     R = pre[R];
             }
             
             if(!bb)pw.println(-1);
         }
         
         
         pw.close();
         
     }
     
 }
class Reader {

    static BufferedReader reader;
    static StringTokenizer tokenizer;

    public static int pars(String x) {
        int num = 0;
        int i = 0;
        if (x.charAt(0) == '-') {
            i = 1;
        }
        for (; i < x.length(); i++) {
            num = num * 10 + (x.charAt(i) - '0');
        }

        if (x.charAt(0) == '-') {
            return -num;
        }

        return num;
    }

    static void init(InputStream input) {
        reader = new BufferedReader(
                new InputStreamReader(input));
        tokenizer = new StringTokenizer("");
    }

    static void init(FileReader input) {
        reader = new BufferedReader(input);
        tokenizer = new StringTokenizer("");
    }

    static String next() throws IOException {
        while (!tokenizer.hasMoreTokens()) {
            tokenizer = new StringTokenizer(
                    reader.readLine());
        }
        return tokenizer.nextToken();
    }

    static int nextInt() throws IOException {
        return pars(next());
    }

    static long nextLong() throws IOException {
        return Long.parseLong(next());
    }

    static double nextDouble() throws IOException {
        return Double.parseDouble(next());
    }
}