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 a[900000], b[900000];
int n, m;
int main() {
  cin >> n >> m;
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
  b[n] = 900000;
  for (int i = n - 1; i >= 1; i--)
    if (a[i] == a[i + 1])
      b[i] = b[i + 1];
    else
      b[i] = i;
  for (int i = 1; i <= m; i++) {
    int l, r, x;
    scanf("%d %d %d", &l, &r, &x);
    if (a[l] != x)
      printf("%d\n", l);
    else {
      if (b[l] >= r)
        printf("%d\n", -1);
      else
        printf("%d\n", b[l] + 1);
    }
  }
}