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.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;


public class Main{
		
		 public static void main(String[] args) throws IOException {
			 	PrintWriter out = new PrintWriter(System.out);
				MyScanner sc = new MyScanner();
				Main solver = new Main();
				solver.solve(out, sc);
				out.flush();
				out.close();
			
		 }
	
		void solve(PrintWriter out, MyScanner sc) throws IOException{	
		
			int n = sc.nextInt();
			int m = sc.nextInt();
			
			int[] a = new int[n];
			for(int i = 0 ; i < n ;++i) {
				a[i] = sc.nextInt();
			}
			
			int[] next = new int[n];
			next[n - 1] = n;
			for(int i = n - 2  ; i >= 0 ; --i) {
				if(a[i] != a[i + 1]) next[i] = i + 1;
				else next[i] = next[i + 1];
			}
			
			outer:
			while(m-- > 0) {
				int l = sc.nextInt() - 1;
				int r = sc.nextInt() - 1;
				int x = sc.nextInt();
				
				while(l <= r) {
					if(a[l] != x) {
						out.println(l + 1);
						continue outer;
					}
					l = next[l];
				}
				out.println(-1);
				
				
			}
			
			
			
		}
		
		
		static class MyScanner {
		    BufferedReader br;
		    StringTokenizer st;

		    public MyScanner() {
		       br = new BufferedReader(new InputStreamReader(System.in));
		    }

		    String next() {
		        while (st == null || !st.hasMoreElements()) {
		            try {
		                st = new StringTokenizer(br.readLine());
		            } catch (IOException e) {
		                e.printStackTrace();
		            }
		        }
		        return st.nextToken();
		    } 

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

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

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

		    String nextLine(){
		        String str = "";
			  try {
			     str = br.readLine();
			  } catch (IOException e) {
			     e.printStackTrace();
			  }
			  return str;
		    }
		    

		}




		
		
		
}