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;
map<int, pair<int, int>> pos;
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  int cur, start = 1;
  scanf("%d", &cur);
  for (int i = 2; i <= n; i++) {
    int a;
    scanf("%d", &a);
    if (a != cur) {
      for (int j = start; j < i; j++) pos[j] = make_pair(i - 1, cur);
      cur = a;
      start = i;
    }
  }
  for (int j = start; j <= n; j++) pos[j] = make_pair(n, cur);
  while (m--) {
    int l, r, x;
    scanf("%d%d%d", &l, &r, &x);
    if (pos[l].second == x) {
      if (pos[l].first < r)
        printf("%d\n", pos[l].first + 1);
      else
        puts("-1");
    } else
      printf("%d\n", l);
  }
  return 0;
}