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.*;
import java.util.*;
 
public class CFEdu7C{
        
    public static void main(String[] args) throws IOException {
              
        FastReader.init(System.in);
        
        PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
     
        int n = FastReader.nextInt();
        int m = FastReader.nextInt();
        int[] a = new int[n];
        int[] b = new int[n];
        int p = 0; 
        int c = 1;      
        for (int i = 0; i < n; i++) {
            a[i] = FastReader.nextInt();
            if (a[i] == p) {
                c++;                
            } else {
                c = 1;                
            }
            p = a[i];
            b[i] = c;
        }
        
        for (int j = 0; j < m; j++) {
            int l = FastReader.nextInt()-1;
            int r = FastReader.nextInt()-1;
            int x = FastReader.nextInt();
            while ((r >= l) && (a[r] == x)) {
                r -= b[r];
            }
            if (r >= l) {
                out.println(r+1);
            } else {
                out.println("-1");
            }
        }
        
        out.close();
    }
}

class FastReader {
    static BufferedReader reader;
    static StringTokenizer tokenizer;

    /** call this method to initialize reader for InputStream */
    static void init(InputStream input) {
        reader = new BufferedReader(
                     new InputStreamReader(input) );
        tokenizer = new StringTokenizer("");
    }

    /** get next word */
    static String next() throws IOException {
        while ( ! tokenizer.hasMoreTokens() ) {
            //TODO add check for eof if necessary
            tokenizer = new StringTokenizer(
                   reader.readLine() );
        }
        return tokenizer.nextToken();
    }

    static int nextInt() throws IOException {
        return Integer.parseInt( next() );
    }
    
    static double nextDouble() throws IOException {
        return Double.parseDouble( next() );
    }
}