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 Main {

	static class PairComparator implements Comparator<Pair> {
		@Override
		public int compare(Pair x, Pair y) {
			if (x.val < y.val)
				return -1;
			if (x.val > y.val)
				return 1;
			if (x.val == y.val) {
				if (x.ind < y.ind)
					return -1;
				if (x.ind > y.ind)
					return 1;
			}
			return 0;
		}
	}

	static class Pair {
		int ind, val;

		Pair(int i, int v) {
			ind = i;
			val = v;
		}
	}


	static void func() throws Exception {
		int n = sc.nextInt();
		int m = sc.nextInt();
		int[] arr = new int[n+1];
		int[] end = new int[n+1];

		for (int i=1;i<=n;i++){
			arr[i] = sc.nextInt();
		}
		for (int i=1;i<=n;i++){
			int r=i+1;
			while (r<=n && arr[i]==arr[r])r++;
			for (int j=i;j<r;j++){
				end[j] = r;
			}
			i=r-1;
		}
		for (int q=0;q<m;q++){
			int l,r,x;
			l = sc.nextInt();
			r = sc.nextInt();
			x = sc.nextInt();
			if (end[l]>r && arr[l]==x){
				pw.println(-1);
				continue;
			}
			while (arr[l]==x)l=end[l];
			pw.println(l);
		}
			


	}

	/*
	 
	 * */
	static PrintWriter pw;
	static MScanner sc;

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

		pw = new PrintWriter(System.out);
		sc = new MScanner(System.in);

		int tests = 1;
	//	tests =sc.nextInt(); //comment this line
		while (tests-- > 0) {
			func();
			pw.flush();
		}

	}

	static class MScanner {
		StringTokenizer st;
		BufferedReader br;

		public MScanner(InputStream system) {
			br = new BufferedReader(new InputStreamReader(system));
		}

		public MScanner(String file) throws Exception {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int[] intArr(int n) throws IOException {
			int[] in = new int[n];
			for (int i = 0; i < n; i++)
				in[i] = nextInt();
			return in;
		}

		public long[] longArr(int n) throws IOException {
			long[] in = new long[n];
			for (int i = 0; i < n; i++)
				in[i] = nextLong();
			return in;
		}

		public int[] intSortedArr(int n) throws IOException {
			int[] in = new int[n];
			for (int i = 0; i < n; i++)
				in[i] = nextInt();
			shuffle(in);
			Arrays.sort(in);
			return in;
		}

		public long[] longSortedArr(int n) throws IOException {
			long[] in = new long[n];
			for (int i = 0; i < n; i++)
				in[i] = nextLong();
			shuffle(in);
			Arrays.sort(in);
			return in;
		}

		public Integer[] IntegerArr(int n) throws IOException {
			Integer[] in = new Integer[n];
			for (int i = 0; i < n; i++)
				in[i] = nextInt();
			return in;
		}

		public Long[] LongArr(int n) throws IOException {
			Long[] in = new Long[n];
			for (int i = 0; i < n; i++)
				in[i] = nextLong();
			return in;
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

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

		public char nextChar() throws IOException {
			return next().charAt(0);
		}

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

		public boolean ready() throws IOException {
			return br.ready();
		}

		public void waitForInput() throws InterruptedException {
			Thread.sleep(3000);
		}
	}

	static void shuffle(int[] in) {
		for (int i = 0; i < in.length; i++) {
			int idx = (int) (Math.random() * (i + 1));
			int tmp = in[i];
			in[i] = in[idx];
			in[idx] = tmp;
		}
	}

	static void shuffle(long[] in) {
		for (int i = 0; i < in.length; i++) {
			int idx = (int) (Math.random() * (i + 1));
			long tmp = in[i];
			in[i] = in[idx];
			in[idx] = tmp;
		}
	}
}