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;
int main() {
  int n, m;
  cin.sync_with_stdio(false);
  cin >> n >> m;
  vector<int> a(n);
  for (int i = 0; i < n; i++) cin >> a[i];
  vector<int> ndiff(n, n);
  for (int i = n - 2; i >= 0; i--) {
    if (a[i + 1] != a[i])
      ndiff[i] = i + 1;
    else
      ndiff[i] = ndiff[i + 1];
  }
  int l, r, x;
  for (int i = 0; i < m; i++) {
    cin >> l >> r >> x;
    if (a[l - 1] != x)
      printf("%d\n", l);
    else if (ndiff[l - 1] < r)
      printf("%d\n", ndiff[l - 1] + 1);
    else
      printf("-1\n");
  }
  return 0;
}