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 CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
struct Event {
  int r, x, idx;
  bool operator<(const Event &e) const {
    return make_pair(x, idx) < make_pair(e.x, e.idx);
  }
};
struct Query {
  int l, r, x, idx;
  bool operator<(const Query &q) const { return l < q.l; }
};
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL), cout.tie(NULL);
  int n, m;
  cin >> n >> m;
  vector<int> data(n);
  for (int &a : data) {
    cin >> a;
  }
  vector<Query> queries;
  for (int i = 0, l, r, x; i < m; ++i) {
    cin >> l >> r >> x;
    queries.push_back({l - 1, r - 1, x, i});
  }
  set<Event> events;
  vector<int> ans(m, -1);
  sort(queries.begin(), queries.end());
  for (int i = 0, j = 0; i < n; ++i) {
    while (j < m && i == queries[j].l) {
      events.insert({queries[j].r, queries[j].x, queries[j].idx}), ++j;
    }
    while (((int)(events).size()) && events.begin()->x < data[i]) {
      if (events.begin()->r >= i) {
        ans[events.begin()->idx] = i + 1;
      }
      events.erase(events.begin());
    }
    while (((int)(events).size()) && events.rbegin()->x > data[i]) {
      if (events.rbegin()->r >= i) {
        ans[events.rbegin()->idx] = i + 1;
      }
      events.erase(*events.rbegin());
    }
  }
  for (int a : ans) {
    cout << a << '\n';
  }
  return 0;
}