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.*;
import java.util.AbstractMap.*;

public class C622 {
	
	public static void main(String args[]) throws Exception {

		InputReader reader = new InputReader(System.in);

		int n = reader.I();
		int m = reader.I();
		int nums[] = new int[n];
		int nextDifferent[] = new int[n];
		for(int i=0;i<n;i++) {
			nums[i] = reader.I();
		}
		nextDifferent[n-1] = -1;
		for(int i=n-2;i>=0;i--) {
			if(nums[i] == nums[i+1]) {
				nextDifferent[i] = nextDifferent[i+1];
			} else {
				nextDifferent[i] = i+1;
			}
		}
		
		
		
		PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
		
		for(int t=0;t<m;t++) {
			int l = reader.I();
			int r = reader.I();
			int x = reader.I();
			l--;r--;
			if(nums[l] != x) {
				out.println(l+1);
			} else {
				int next = nextDifferent[l];
				if(next != -1 && next <= r) {
					out.println(next+1);
				} else {
					out.println(-1);
				}
			}
		}
		
		out.close();
	}
        
	

	static BufferedReader br;
    static long M = (long) 1e9 + 7;

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int I() {
            return Integer.parseInt(next());
        }

    }
}