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 static java.lang.Math.*;
public class Main {
    static final long MOD = 1_000_000_007 , INF = 1_000_000_000_000_000_000L;
    static final int INf = 1_000_000_000;
    static FastReader reader;
    static PrintWriter writer;
    public static void main(String[] args) {
        Thread t = new Thread(null, new O(), "Integer.MAX_VALUE", 100000000);
        t.start();
    }
    static class O implements Runnable {
        public void run() {
            try {
                magic();
            }
            catch (Exception e) {
                e.printStackTrace();
                System.exit(1);
            }
        }
    }
    static class FastReader {
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;

        public FastReader() {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public FastReader(String file_name) throws IOException {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public String readLine() throws IOException {
            byte[] buf = new byte[1000000];
            int cnt = 0, c;
            while ((c = read()) != -1) {
                if (c == '\n') break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }

        public int nextInt() throws IOException {
            int ret = 0;
            byte c = read();
            while (c <= ' ') c = read();
            boolean neg = (c == '-');
            if (neg) c = read();
            do {
                ret = ret * 10 + c - '0';
            } while ((c = read()) >= '0' && c <= '9');
            if (neg) return -ret;
            return ret;
        }

        public long nextLong() throws IOException {
            long ret = 0;
            byte c = read();
            while (c <= ' ') c = read();
            boolean neg = (c == '-');
            if (neg) c = read();
            do {
                ret = ret * 10 + c - '0';
            } while ((c = read()) >= '0' && c <= '9');
            if (neg) return -ret;
            return ret;
        }

        public double nextDouble() throws IOException {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ') c = read();
            boolean neg = (c == '-');
            if (neg) c = read();
            do {
                ret = ret * 10 + c - '0';
            } while ((c = read()) >= '0' && c <= '9');
            if (c == '.') while ((c = read()) >= '0' && c <= '9') ret += (c - '0') / (div *= 10);
            if (neg) return -ret;
            return ret;
        }

        private void fillBuffer() throws IOException {
            bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
            if (bytesRead == -1) buffer[0] = -1;
        }

        private byte read() throws IOException {
            if (bufferPointer == bytesRead) fillBuffer();
            return buffer[bufferPointer++];
        }

        public void close() throws IOException {
            if (din == null) return;
            din.close();
        }
    }

    static void magic() throws IOException {
        reader = new FastReader();
        writer = new PrintWriter(System.out, true);
        ArrayList<Query> query_list[] = new ArrayList[1000001];
        ArrayList<Integer> occ[] = new ArrayList[1000001];
        for(int i=1;i<=1000000;++i) {
            occ[i] = new ArrayList<>();
            query_list[i] = new ArrayList<>();
        }
        int n = reader.nextInt(), m = reader.nextInt();
        for(int i=1;i<=n;++i) {
            int x = reader.nextInt();
            occ[x].add(i);
        }
        for(int i=0;i<m;++i) {
            int l = reader.nextInt(), r = reader.nextInt(), val = reader.nextInt();
            query_list[val].add(new Query(l,r,i));
        }
        int ans[] = new int[m];
        TreeSet<Integer> curr = new TreeSet<>();
        for(int i=1;i<=n;++i) {
            curr.add(i);
        }
        for(int i=1;i<=1000000;++i) {
            for(int e : occ[i]) {
                curr.remove(e);
            }
            for(Query q : query_list[i]) {
                Integer next_higher = curr.higher(q.l-1);
                if(next_higher!=null && next_higher<=q.r) {
                    ans[q.idx] = next_higher;
                }
                else {
                    ans[q.idx] = -1;
                }
            }
            for(int e : occ[i]) {
                curr.add(e);
            }
        }
        StringBuilder fast = new StringBuilder();
        for(int e : ans) {
            fast.append(e);
            fast.append("\n");
        }
        writer.print(fast);
        writer.println();
    }
    static class Query {
        int l,r,idx;
        public Query(int l, int r, int idx) {
            this.l = l;
            this.r = r;
            this.idx = idx;
        }
    }
}